EXPLANATION  OF  PLATE  I. 

[Figures  1  to  8,  inclusive,  natural  Bice.] 


GYPSY  MOTH,  Porthetria  dispar  (L.). 


Fig.   i.  Female  with  the  wings  spread. 

2.  Female  with  the  wings  folded. 

3.  Male  with  the  wings  spread. 

4.  Male  with  the  wings  folded. 

5.  Pupa. 

6.  Caterpillar. 

Full  grown. 


mlar.  \ 
rillar.  I 


7.  Caterpillar 

8.  Cluster  of  eggs  on  bark. 

9.  Several  eggs  enlarged. 

10.  One  egg  greatly  enlarged. 


PLATE  I 


Drawn  Wj  Joseph  Bridgham . 


GYPSY'V 


MOTH,. 


THE  GYPSY  MOTH. 

PORTHETRIA   DI8PAR   (LlNN.). 


A  REPORT  OF  THE 


OF   DESTROYING    THE  INSECT   IN   THE    COMMONWEALTH   OF 

MASSACHUSETTS,  TOGETHER  WITH  AN  ACCOUNT 

OF  ITS  HISTORY  AND  HABITS  BOTH  IN 

MASSACHUSETTS  AND  EUROPE. 


BY 

EDWARD    H.    FORBUSH, 

FIELD  DIRECTOR  IN  CHARGE  OP  THE  WORK  OF  DESTROYING  THE  GYPST  MOTH, 
ORNITHOLOGIST  TO  THE  STATE  BOARD  OP  AGRICULTURE, 
PRESIDENT    OP   THE  WORCESTER   NATURAL 
HISTORY  SOCIETY,  ETC., 


AND 

CHARLES  H.  FERNALD,  A.M.,  Pn.D., 

PROFESSOR  OF  ZOOLOGY  IN  THE  MASSACHUSETTS  AGRICULTURAL  COLLEGE, 
ENTOMOLOGIST  TO  THE  STATE  BOARD  OF  AGRICULTURE, 
ENTOMOLOGIST  TO  THE  HATCH  EXPERI- 
MENT STATION,  ETC. 


PUBLISHED  UNDER  THE  DIRECTION  OF  THE  STATE  BOARD  OF  AGRICULTURE; 
BY  AUTHORITY  OF  THE  LEGISLATURE. 


BOSTON : 

WRIGHT  &  POTTER  PRINTING  CO.,  STATE  PRINTERS, 

18  POST  OFFICE  SQUARE. 

1896. 


LETTER    OF    SUBMITTAL. 


BOSTON,  Jan.  1,  1896. 
To  the  Massachusetts  State  Board  of  Agriculture. 

GENTLEMEN  :  —  We  have  the  honor  to  submit  herewith 
the  report  on  the  gypsy  moth,  which  has  been  prepared 
under  our  direction,  as  authorized  by  chapter  71,  Kesolves 
of  1894. 

Respectfully, 

E.  W.  WOOD, 
AUGUSTUS  PRATT, 

F.  W.  SARGENT, 
J.  G.  AVERT, 

S.    S.    STETSON, 
WM.   R.    SESSIONS, 

Committee  on  the  Gypsy  Moth. 


CO^TEKTS. 


Page 

PREFACE,       .   ' ix 

THE  GYPSY  MOTH,  Porthetria  dispar  (L.). 
Part  I.,  E.  H.  FORBUSH. 

The  gypsy  moth :  its  history  in  America, 3 

Its  introduction 3 

The  unnoticed  increase  of  the  moth,     , 4 

Influences  that  at  first  retarded  its  increase, 5 

The  first  destructive  appearance  of  the  moth, 7 

The  outbreak  of  1889, .M 

The  swarming  caterpillars  become  a  serious  nuisance,        ....  14 

The  destructiveness  of  the  moth, 23 

How  the  people  fought  the  moth, 28 

The  matter  brought  to  the  attention  of  the  public  at  large, ....  32 

The  commission  of  1890, 38 

The  work  of  1891 '45 

The  work  of  1892, 62 

The  work  of  1893, 68 

The  work  of  1894 72 

The  work  of  1895 83 

The  number  of  men  employed  and  work  done,  1890  to  1894  inclusive,      .        .  89 

The  increase  and  distribution  of  the  gypsy  moth 94 

The  rate  of  increase 94 

Distribution  as  affected  by  food  supply  and  other  natural  causes,      .        .  97 

The  connection  of  distribution  and  population 99 

The  distribution  of  the  moth  by  man's  agency, 100 

A  study  of  the  methods  and  routes  of  transportation, 106 

The  effect  of  the  work  of  extermination  on  the  distribution  of  the  gypsy 

moth 113 

Methods  used  for  destroying  the  gypsy  moth, 117 

The  destruction  of  the  eggs, 117 

The  destruction  of  the  caterpillars 126 

Measures  for  destroying  all  forms  of  the  moth, 164 

A  summary  of  the  methods  most  useful  to  the  farmer,       ....  194 

The  annual  inspection,  .                196 

Measures  for  the  information  of  the  public, 198 

Natural  enemies  of  the  gypsy  moth, 203 

Insect-eating  birds, 203 

Birds  seen  to  feed  upon  the  gjpsy  moth, 207 

The  progress  of  extermination, 244 

THE  GYPSY  MOTH,  Porthetria  dispar  (L.). 
Part  II.,  C.  H.  FERNALD. 

Scientific  and  common  names, 255 

Bibliography, 257 

Distribution  in  other  countries, 267 

The  gypsy  moth  in  England, 268 

Injuries  in  the  old  world, 273 

Methods  of  destroying  the  gypsy  moth  in  Europe, 284 


viii  CONTENTS. 

Page 
288 

Scattered  eggs, 290 

Date  of  hatching, 294 

A  second  brood,  .  295 

The  larva  or  caterpillar 299 

Feeding  habits, 311 

Process  of  pupation, 332 

The  pnpa,  * "...  333 

Pupation  in  the  field,  ............  335 

The  imago 336 

Mating, 342 

Habits  of  flight, 344 

The  assembling  of  the  gypsy  moth, 345 

On  trapping  males, .357 

Opposition, 363 

Parthenogenesis, ...  365 

Internal  anatomy, 368 

Natural  enemies  of  the  gypsy  moth 375 

Hymenoptera, 375 

Coleoptera, 381 

Diptera, 385 

Hemlptera, 392 

Spiders 404 

Insectivorous  vertebrates 404 

Vegetable  parasites, 405 

Insecticides • 407 

Analyses  of  poisoned  larvae 474 

Effects  of  insecticides  on  foliage, 489 

Analyses  of  insecticides, 492 

Leaf  area  of  trees 494 

APPENDICES : — 

Appendix  A,  report  of  a  conference  held  at  the  rooms  of  the  State  Board  of 

Agriculture,  Boston,  Mass.,  March  4,  1891, iii 

Appendix  B,  revised  rules  and  regulations  adopted  by  the  State  Board  of 

Agriculture xx 

Appendix  C,  an  extract  from  a  description  of  Section  8,  Medford,  as  it  appears 
in  the  section  book,  showing  the  condition  of  that  section  and  the 

work  done  in  it  in  1891, xxvii 

Appendix  D,  reports  of  entomologists  who  visited  the  infested  region  in  1893,  xxxii 

Appendix  E,  reports  of  entomologists  who  visited  the  infested  region  in  1894; 

opinion  of  the  United  States  entomologist, xliii 

Appendix  F,  the  dangers  of  arsenical  poisoning  resulting  from  spraying  with 

insecticides, lii 

Appendix  G,  a  list  of  correspondents  and  observers  who  have  furnished  in- 
formation in  regard  to  the  gypsy  moth  in  Massachusetts,  .  .  .  Iviii 


PREFACE. 


This  report  is  respectfully  submitted  for  the  benefit  of 
the  people  of  Massachusetts,  especially  those  residing  in 
the  district  infested  by  the  gypsy  moth,  who  have  suffered 
from  the  injuries  inflicted  by  the  insect.  The  design  of  the 
report  is  to  present,  within  the  prescribed  limits,  as  full  a 
history  as  possible  of  what  is  known  about  the  gypsy  moth 
in  Massachusetts ;  also  to  give  a  brief  r6sum6  of  its  history 
abroad.  We  have  endeavored  to  present  most  folly  those 
features  of  the  subject  which  are  most  important  from  a 
practical  and  economic  standpoint.  That  clause  in  chapter 
71  of  the  Eesolves  of  1894  which  authorizes  the  prepara- 
tion for  printing  "of  the  scientific  facts  ascertained"  has 
been  kept  in  view,  and  much  matter  of  a  more  or  less  scien- 
tific or  technical  nature,  which  has  come  under  our  notice  in 
connection  with  the  field  work  or  while  making  the  inves- 
tigations and  experiments  with  which  we  have  been  charged, 
has  been  recorded  in  this  volume.  The  investigations  of 
the  life  history  and  habits  of  many  of  those  forms  of  animal 
life  which  exert  controlling  influences  upon  the  gypsy  moth 
have  not  yet  proceeded  far  enough  to  allow  the  results  to  be 
fully  chronicled.  A  summary  of  the  results  of  some  of  the 
most  important  experiments  is  given,  and,  where  observa- 
tions have  been  made  by  a  sufficient  number  of  individuals 
to  warrant  the  drawing  of  conclusions,  such  conclusions 
have  been  recorded.  A  further  study  of  the  parasites  and 
enemies  of  the  gypsy  moth  is  in  progress. 

Part  I.  of  this  volume  records  such  of  the  most  impor- 


x  PREFACE. 

tant  results  attained  by  the  State  Board  of  Agriculture  in 
the  work  of  exterminating  the  gypsy  moth  as  could  be  in- 
cluded within  the  limits  of  the  space  allowed  to  the  report. 
Part  n.,  besides  giving  the  bibliography  of  the  moth  and 
instances  of  its  injuries  in  Europe,  deals  especially  with  the 
"scientific  facts  ascertained,"  and  chronicles  many  of  the 
more  important  experiments  made  with  a  view  of  finding 
means  to  check  the  ravages  of  the  insect  and  secure  its 
extermination. 

The  authors  are  well  aware  of  many  shortcomings  in  the 
work.  They  have  labored  under  the  disadvantage  of  resid- 
ing in  different  parts  of  the  State,  and  therefore  have  not 
had  opportunity  to  consult  together  and  compare  notes  as 
often  as  was  desirable.  All  responsibility  for  error  in 
either  part  will  be  assumed  individually  by  the  author  to 
whom  that  part  is  accredited.  Other  duties  which  were 
imperative  in  their  demands  upon  our  capacity  for  labor 
have  at  times  prevented  that  painstaking  revision  which 
such  work  requires.  Much  valuable  information  has  neces- 
sarily been  excluded  for  lack  of  space.  It  was  impossible, 
for  instance,  to  quote  fully  from  accounts  of  injuries  com- 
mitted by  the  moth  in  Europe.  For  the  same  reason,  one 
hundred  and  forty-six  statements  in  regard  to  the  ravages 
of  the  moth,  from  residents  of  the  infested  district  in  Mas- 
sachusetts, have  been  omitted.  Extracts  from  some  of  them 
are  given,  however,  in  Part  I.  Most  of  that  portion  of 
Part  I.  which  is  devoted  to  spraying  was  prepared  in  1894, 
and  cannot  be  considered  as  up  to  date,  as  spraying  has  not 
been  one  of  the  chief  methods  employed  in  the  field  work 
of  the  last  two  years. 

The  Appendices  relate  largely  to  the  views  expressed  by 
certain  eminent  entomologists  in  regard  to  the  work  of  ex- 
termination. Appendix  F,  on  the  dangers  attendant  on 


PREFACE.  xi 

arsenical  poisoning  by  spraying,  was  written  by  Mr.  For- 
bush. 

The  drawings  for  the  insect  plates  were  made  by  Mr, 
Joseph  Bridgham,  Miss  Ella  M.  Palmer  and  Mr.  J.  H. 
Emerton.  The  drawings  of  appliances  and  tools  were  made 
by  Mr.  C.  A.  King.  Messrs.  A.  H.  Kirkland,  R.  A.  Cooley 
and  C.  P.  Lounsbury  made  the  drawings  for  the  anatomical 
plates.  Most  of  the  other  drawings  were  made  by  Mr. 
Kirkland. 

We  are  under  obligations  to  the  Boston  Woven  Hose  and 
Rubber  Company,  W.  &  B.  Douglass,  Gould  Manufacturing 
Company,  A.  H.  Nixon  and  John  J.  McGowen  for  cuts 
of  spraying  apparatus ;  also  to  Estes  &  Lauriat  for  three 
cuts  from  "  Coues'  Key  to  North  American  Birds,"  Little, 
Brown  &  Company  for  three  cuts  from  Baird,  Brewer  and 
Ridgway's  "North  American  Birds,"  and  J.  B.  Lippincott 
for  two  cuts  from  "  Birds  About  Us,"  by  Dr.  C.  C.  Abbott. 

It  only  remains  to  perform  the  pleasant  duty  of  acknowl- 
edging the  many  favors  which  have  been  bestowed  upon  us 
by  those  who  have  assisted  in  the  preparation  of  this  work. 
Acknowledgments  are  due  to  the  scores  of  foreign  corre- 
spondents, both  eminent  naturalists  and  government  officials, 
who  have  furnished  information,  and  also  to  residents  of 
the  infested  district,  who  have  given  useful  information, 
and  whose  names  appear  in  Appendix  G.  In  our  biblio- 
graphical researches  we  have  been  most  courteously  and  ably 
assisted  by  the  officials  of  the  Boston  Public  Library  and 
those  of  the  libraries  of  Harvard  University,  Museum  of 
Comparative  Zoology,  Arnold  Arboretum,  Boston  Society 
of  Natural  History,  Boston  Athenaeum,  Massachusetts  Horti- 
cultural Society  and  Massachusetts  Agricultural  College. 
To  Mr.  Samuel  Henshaw  we  are  especially  indebted  for 
assistance  in  obtaining  many  references  concerning  the 


xii  PREFACE. 

history  of  the  gypsy  moth  in  Europe ;  and  to  Dr.  F.  B. 
Stephenson,  U.  S.  N.,  for  the  translation  of  Russian  works. 

We  are  greatly  indebted  to  Messrs.  J.  A.  Farley  and  A. 
H.  Kirkland  for  very  valuable  services  in  connection  with 
the  preparation  of  the  report.  Mr.  Farley,  who  has  made  an 
exhaustive  study  of  the  distribution  of  the  gypsy  moth,  has 
contributed  the  material  for  that  portion  of  the  paper  on 
distribution  which  treats  of  the  ' '  methods  and  routes  of 
transportation."  While  certain  portions  of  Part  II.  are 
credited  in  the  text  to  Mr.  Kirkland,  he  has  been  of  great 
assistance  to  the  authors  in  many  other  ways.  Messrs.  F. 
H.  Jones,  F.  A.  Bates  and  C.  W.  Minott  have  rendered 
much  aid  in  the  way  of  criticism  and  suggestion.  Lack  of 
space  forbids  the  mention  by  name  of  the  scores  and  even 
hundreds  of  other  intelligent  observers,  more  or  less  per- 
manently connected  with  the  work,  who  have  furnished  use- 
ful notes. 

The  main  credit  for  the  production  of  this  volume  is  due 
to  the  committee  of  the  State  Board  of  Agriculture,  who 
have  for  five  years  conducted  the  work  with  the  steadfast 
purpose  of  ridding  the  Commonwealth  of  the  gypsy  moth. 
They  have  recommended  that  the  Legislature  authorize  the 
preparation  and  printing  of  the  report.  They  have  con- 
ferred upon  us  the  honor  of  preparing  the  volume,  and  our 
thanks  are  due  to  them  for  endorsement  of  our  plans  and 
for  their  constant  and  consistent  support. 

THE   AUTHORS. 


THE     GYPSY    MOTH 

PORTHETRIA    DISPAR     (L.)  . 


IE. 


THE  GYPSY  MOTH 

ITS  HISTORY  IN  AMERICA. 


ITS  INTRODUCTION. 

The  gypsy  moth(Porthetria  dispar)&  pest  of  European 
countries,  was  introduced  into  America  in  1868  or  1869 
by  Leopold  Trouvelot,  a  French  artist,  naturalist  and  astron- 
omer of  note.  Prof.  C.  V.  Riley,  then  State  entomologist 
of  Missouri,  recorded  the  occurrence  in  1870  in  these  words  : 
"  Only  a  year  ago  the  larva  of  a  certain  owlet  moth  (Hy- 
pogymna  dispar}  which  is  a  great  pest  in  Europe  both  to 
fruit  trees  and  forest  trees,  was  accidentally  introduced  by  a 
Massachusetts  entomologist  into  New  England,  where  it  is 
spreading  with  great  rapidity."  * 

Though  Professor  Riley  did  not  then  mention  Trouvelot 
or  Medford,  the  facts  were  evidently  well  known  to  him,  as 
twenty  years  later  he  wrote  in  ''Insect  Life"  as  follows: 
"  This  conspicuous  insect,  although  not  recorded  in  any  of 
our  check  lists  of  North  American  Lepidoptera,  has  un- 
doubtedly been  present  in  a  restricted  locality  in  Massachu- 
setts for  about  twenty  years.  It  was  imported  by  Mr.  L. 
Trouvelot  in  the  course  of  his  experiments  with  silk-worms, 
recorded  in  the  early  volumes  of  the  ' American  Naturalist,' 
and  certain  of  the  moths  escaping,  he  announced  the  fact 
publicly,  and  we  mentioned  it  in  the  second  volume  of  the 
'American  Entomologist,'  page  111  (1870),  and  in  our 
''Second  Report  on  the  Insects  of  Missouri,'  page  10. "f 

In  a  Bulletin  of  the  Hatch  Experiment  Station,  published 
in  November/ 1889,  Prof.  C.  H.  Fernald  wrote:  "Mr. 
Samuel  Henshaw  and  Dr.  Hagen(of  Cambridge  have  both 
informed  me  that  the  entomologist  who  introduced  this 

*  Riley's  Second  Report  on  Insects  of  Missouri,  page  10. 
t  Insect  Life,  Vol.  II.,  No.  7,  8,  page  208. 


4  THE   GYPSY  MOTH. 

insect  was  Mr.  L.  Trouvelot,  now  living  in  Paris,  but  at 
that  time  living  near  Glenwood,  Medford,  where  he  at- 
tempted some  experiments  in  raising  silk  from  our  native 
silk-worms,  and  also  introduced  European  species  for  the 
same  purpose.  Dr.  Hagen  told  me  that  he  distinctly  remem- 
bered hearing  Mr.  Trouvelot  tell  how  they  escaped  from 
him  after  he  had  imported  them." 

Prof.  N.  S.  Shaler  of  Harvard  University,  who  knew  Mr. 
Trouvelot,  has  also  stated  to  the  writer  that  he  remembers 
hearing  Mr.  Trouvelot  speak  of  the  importation  and  escape. 
Thus  we  have  evidence  from  eminent  scientific  authorities 
that  settles  beyond  doubt  the  approximate  time  and  the  place 
of  introduction  of  this  insect,  and  who  was  responsible  for  it. 
During  his  sojourn  in  Medford  Mr.  Trouvelot  lived  in  a 
house  (now  known  as  No.  27  Myrtle  Street)  near  Glenwood 
station  on  the  Medford  branch  of  the  Boston  &  Maine  Rail- 
road. It  is  said  by  people  who  lived  in  the  vicinity  in  1869 
that  he  imported  some  insects'  eggs  about  that  time,  some 
of  which  were  blown  out  of  a  window  of  the  room  in  which 
they  were  kept,  and  that  he  was  much  disturbed  on  being 
unable  to  find  them.  Others  state  that  the  insects  escaped 
in  the  larval  form.  Probably  the  insect  was  imported  in  the 
egg.  Its  escape  seems  to  have  been  accidental,  and  Trou- 
velot, being  aware  of  the  dangerous  character  of  the  pest, 
and  finding  his  efforts  for  its  eradication  futile,  gave  public 
notice  of  the  fact  that  the  moth  had  escaped  from  his  custody. 

THE  UNNOTICED  INCREASE  OF  THE  MOTH. 

The  historian  is  considerably  embarrassed  by  lack  of  evi- 
dence in  regard  to  the  increase  and  spread  of  the  moth  dur- 
ing the  first  ten  years.  No  one  except  Trouvelot  is  known 
to  have  observed  it  during  any  portion  of  that  time.  For 
most  of  the  evidence  of  its  spread  and  ravages  during  the 
decade  from  1879  to  1889  we  must  depend  on  the  testimony 
of  residents  of  Medford  and  Maiden.  Much  information 
bearing  on  the  subject  has  been  obtained  during  the  past 
three  years,  letters  and  carefully  revised  statements  having 
been  received  from  a  large  number  of  people  in  these  cities. 

For  several  years  after  the  moth  escaped,  it  attracted  no 
attention  in  Medford.  People  who  witnessed  in  1889  the 


ITS   INCREASE   RETARDED.  5 

first  extensive  outbreak  of  the  moth  in  Medford,  and  thus 
became  acquainted  with  its  voracity  and  reproductive  pow- 
ers, were  unable  to  understand  how  so  destructive  a  creat- 
ure could  have  existed  unnoticed  for  twenty  years.  But 
the  moth  was  not  unnoticed  after  the  first  ten  years,  al- 
though its  identity  remained  unknown  and  its  spreading 
attracted  no  attention  outside  the  locality  where  it  was  first 
introduced.  Within  twelve  years  from  the  time  of  its 
introduction  it  had  become  a  serious  nuisance  to  those 
living  in  and  near  the  Trouvelot  house ;  but  they  then  sup- 
posed the  caterpillar  to  be  a  native.  Its  lack  of  conspicuous 
markings,  which  to  the  common  eye  would  distinguish  it 
from  other  species,  and  its  habits  of  concealment  and  night- 
feeding  will  explain  its  unheeded  distribution.  Within 
twenty  years  it  had  spread  into  thirty  townships  and  gained 
a  foothold  in  each  without  attracting  public  attention.  Of 
these  facts  we  have  the  most  convincing  proofs. 

INFLUENCES  THAT  AT  FIRST  RETARDED  ITS  INCREASE. 

A  study  of  the  growth  of  many  isolated  moth  colonies 
which  have  been  found  existing  under  conditions  similar  to 
those  influencing  the  Trouvelot  colony,  gives  abundant  proof 
that  the  growth  of  such  swarms  for  the  first  few  years  is  ex- 
ceedingly slow. 

The  experiments  made  have  not  yet  shown  conclusively 
how  much  the  enforced  and  continuous  inbreeding  which  re- 
sults from  isolation  affects  the  vitality  of  the  species.  Field 
observations  show  that  in  some  cases  isolated  colonies  have 
come  very  near  extinction  in  the  first  years  of  their  exist- 
ence, while  others  have  died  out.  During  the  eight  or  ten 
years  following  its  introduction,  the  moth,  while  becoming 
acclimated,  battled  against  the  many  influences  which  served 
at  first  to  hold  it  in  check.  A  consideration  of  the  oper- 
ation of  these  influences  will  go  far  toward  explaining  its 
apparently  slow  increase  during  the  first  few  years.  It  must 
be  considered  that  the  nev/ -comer  had  much  to  contend 
against.  It  had  to  encounter :  — 

1.  A  new  and  changeable  climate.  How  potent  were  cli- 
matic influences  in  controlling  the  increase  of  the  species? 
Such  influences  may  have  been  felt  for  years.  If  the  moth 


6  THE  GYPSY  MOTH. 

was  introduced  from  France,  our  harsher  climate  may  have 
destroyed  many  of  the  smaller  caterpillars  before  they  had 
attained  strength  enough  to  resist  exposure  to  its  sudden 
changes.  A  warm  period  early  in  the  season,  followed  by  a 
cold  storm  or  severe  frost,  sometimes  destroys  many  of  the 
young  caterpillars.  They  are  first  hatched  by  the  unseta- 
sonable  warmth,  and  then  killed  by  the  cold  immediately 
following. 

2.  Isolation,  with  all  its  attendant  perils.  The  isolation 
of  the  species  and  its  small  numbers  rendered  it  peculiarly 
sensitive  to  the  attacks  of  new  enemies  which  surrounded  it. 
Parasitic  and  predaceous  insects  were  no  doubt  plentiful 
then,  as  they  are  to-day.  The  topography  of  the  locality 
and  the  vegetation  of  the  neighborhood  were  such  as  to  ren- 
der it  specially  attractive  as  a  breeding  ground  for  insect- 
eating  birds.  Myrtle  Street  was  then  flanked  by  gardens 
and  orchards,  and  nearly  surrounded  by  woodland  and  bushy 
pasture.  Not  far  to  the  east  is  a  small  swamp  and  stream, 
and  the  whole  locality  lies  near  the  marshy  banks  of  the 
Mystic  River.  Many  of  the  birds  which  frequent  such  places 
feed  on  the  gypsy  moth  in  one  or  more  of  its  forms  wher- 
ever it  is  found.  It  is  related  in  Samuels's  "  Birds  of  New 
England,"  published  in  1870,  that  Mr.  Trouvelot,  who  was 
then  engaged  in  rearing  silk-worms,  placed  two  thousand  of 
them  on  a  small  oak  in  front  of  his  house,  and  that  in  a  few 
days  they  were  all  eaten  by  robins  and  catbirds.  He  had  a 
large  area  of  woodland  fenced  in  and  covered  with  netting 
to  protect  his  silk-worms.  The  birds  came  from  all  quarters 
to  feed  on  the  worms,  breaking  through  the  netting,  so 
that  he  was  obliged  to  shoot  them  in  defence  of  his  "infant 
industry."  *  Mr.  Trouvelot,  in  describing  his  work  on  the 
American  silk- worm  (Telea  polyphemus},  says  that  it  is 
probable  that  ninety-five  out  of  a  hundred  worms  become 
the  prey  of  birds,  f 

At  that  time  the  cuckoos,  blue-jays,  orioles,  vireos,  cat- 
birds, bluebirds  and  warblers  which  are  known  to  feed  upon 
the  caterpillars  were  also  abundant  in  that  locality  during 
the  season  when  the  caterpillars  were  feeding.  The  inroads 


*  Birds  of  New  England,  page  Io6.        f  American  Naturalist,  Vol.  I.,  page  89. 


ITS   EARLY  HISTORY.  7 

made  at  first  by  birds  alone  on  the  comparatively  small  num- 
ber of  caterpillars  would  have  been  sufficient  to  hold  them  in 
check.  Fly-catchers  secure  many  of  the  moths  also ;  other 
birds  destroy  the  pupse.  The  restraining  influence  exerted 
by  birds  and  predaceous  insects  would  be  greater  in  propor- 
tion when  the  moths  were  comparatively  few. 

3.  Forest  or  brush  fires.  The  locality  in  which  the  moth 
was  first  liberated  was  favorable  for  its  unnoticed  increase 
and  spread,  as  there  were  many  forest  trees  and  a  dense 
undergrowth  in  the  vicinity,  which  afforded  it  a  liberal  food 
supply.  Undoubtedly  it  was  somewhat  checked  in  this  waste 
land  during  the  first  few  years  by  fires,  which  frequently  oc- 
curred in  the  woodland  near  the  Trouvelot  house.  Such 
fires  destroy  some  eggs  of  the  moth  which  are  deposited  near 
the  ground,  and  are  also  very  destructive  in  the  spring  to  the 
young  larvae.  Mr.  John  Crowley,  formerly  one  of  the  select- 
men of  Medford,  speaks  of  these  fires  as  follows :  — 

Glenwood,  twenty-one  years  ago,  was  a  thinly  settled  district 
and  consisted  largely  of  brush  land.  There  were  brush  fires  there 
every  year.  The  fire  department  was  called  out  twice  in  one  year 
because  dwellings  were  in  danger.  I  think  the  frequent  brush 
fires  held  the  moth  in  check  for  many  years,  and  will  explain  why 
they  were  so  slow  in  making  their  appearance  in  the  orchard  and 
shade  trees  of  other  sections. 

THE  FIRST  DESTRUCTIVE  APPEARANCE  OF  THE  MOTH. 

After  the  first  ten  or  twelve  years  following  their  intro- 
duction the  moths  increased  so  rapidly  that  the  larvas  did 
considerable  damage  in  the  immediate  vicinity  of  Mr. 
Trouvelot's  house,  according  to  testimony  of  people  in  the 
neighborhood.  During  the  first  few  years  of  their  abun- 
dance the  insects  spread  along  Myrtle  Street  and  into  the 
woodland  and  swamp  at  the  south,  across  the  railroad,  but 
did  not  for  some  years  become  numerous  or  destructive  north 
of  the  street. 

That  the  moth  did  not  increase  faster  and  spread  more 
rapidly  to  other  parts  of  Medford  is  largely  due  to  the  efforts 
of  certain  residents  of  Myrtle  Street,  who  for  ten  or  twelve 
years  persistently  fought  the  pest  on  their  own  property. 


8  THE   GYPSY  MOTH. 

That  their  efforts  were  finally  without  avail  is  true,  but  it 
might  have  been  otherwise  had  the  moths  not  remained 
unmolested  in  the  woodland  near  by,  from  which,  whenever 
food  became  insufficient,  they  sallied  out  and  overwhelmed 
the  near  gardens  and  orchards. 

Mr.  William  Taylor,  No.  19  Myrtle  Street,  speaking  of 
the  years  from  1879  to  1889,  said  :  — 

In  the  fall  of  1879  I  moved  to  27  Myrtle  Street,  where  Mr. 
Trouvelot,  who  brought  the  gypsy  moth  to  this  country,  formerly 
lived.  In  the  following  spring  I  found  the  shed  in  the  rear  of  his 
house  swarming  with  caterpillars.  I  knew  that  Mr.  Trouvelot 
had  been  experimenting  with  silk-worms,  but  I  did  not  know  that 
the  swarms  of  caterpillars  in  the  shed  came  from  the  gypsy  moth. 
The  caterpillars  were  such  a  nuisance  in  and  around  the  shed  that 
I  got  permission  to  sell  it,  and  it  was  taken  to  Mr.  Harmon's  on 
Spring  Street.  This  will  explain  how  the  moth  was  carried  into 
that  section,  and  why  the  woods  there  became  so  badly  infested. 
I  fought  the  caterpillars  of  the  gypsy  moth  for  ten  years  before 
the  State  did  anything.  In  their  season  I  used  to  gather  them 
literally  by  the  quart  before  going  to  work  in  the  morning. 

Mr.  and  Mrs.  William  Belcher,  well-known  residents  cf 
Glenwood,  still  residing  at  No.  29  Myrtle  Street,  have  had 
the  best  of  opportunities  to  observe  the  increase  of  the  in- 
sect in  that  vicinity.  Mrs.  Belcher  writes  as  follows  :  — 

Mr.  Trouvelot,  who  is  said  to  have  introduced  the  gypsy  moth 
into  this  country,  was  a  next-door  neighbor  of  ours.  The  cater- 
pillars troubled  us  for  six  or  eight  years  before  they  attained  to 
their  greatest  destructiveness.  This  was  in  1889.  They  were  all 
over  the  outside  of  the  house,  as  well  as  the  trees.  All  the  foli- 
age was  eaten  off  our  trees,  the  apples  being  attacked  first  and  the 
pears  next. 

Mrs.  J.  W.  Flinn  of  Maiden,  who  lived  in  Glenwood  near 
Mr.  Trouvelot's  house  during  a  part  of  this  decade,  says :  — 

We  moved  to  Myrtle  Street,  Medford,  in  1882,  and  that  year  the 
gypsy-moth  caterpillars  were  very  troublesome  in  our  yard  and  in 
those  of  our  immediate  neighbors.  At  that  time  they  were  con- 
fined to  our  part  of  Myrtle  Street,  but  they  soon  spread  in  all 
directions.  The  caterpillars  were  over  everything  in  our  yard  and 


ITS  FIRST  RAVAGES.  9 

stripped  all  our  fruit  trees,  taking  the  apple  trees  first  and  then 
the  pears.  There  was  a  beautiful  maple  on  the  street  in  front  of 
the  next  house,  and  all  its  leaves  were  eaten  by  the  caterpillars. 
They  got  from  the  ground  upon  the  house  and  blackened  the  front 
of  it.  ...  The  caterpillars  would  get  into  the  house  in  spite  of 
every  precaution,  and  we  would  even  find  them  upon  the  clothing 
hanging  in  the  closets.  We  destroyed  a  great  many  caterpillars 
by  burning,  but  their  numbers  did  not  seem  to  be  lessened  in  the 
least.  Other  neighbors  did  not  fight  the  caterpillars  as  we  did, 
and  so  our  efforts  were  in  a  measure  rendered  abortive.  I  think 
perhaps  that  if  an  organized  effort  had  been  made  at  that  time  to 
destroy  the  caterpillars  they  might  have  been  stamped  out.  We 
lived  on  Myrtle  Street  for  four  years,  and  every  year  had  the  same 
plague. 

It  should  be  noted  that  the'  Flinn  family  moved  from 
Myrtle  Street  in  1886,  having  suffered  from  the  pest  from 
1882  until  that  time,  which  was  three  years  before  it  became 
generally  prevalent.  Although  the  moths  were  so  numerous 
near  the  Trouvelot  house  from  1880  to  1885,  they  did  not 
become  a  serious  pest  farther  down  the  street  until  about 
1886.  We  quote  Mrs.  M.  F.  Fenton  :  — 

In  1886  we  lived  at  No.  10  Myrtle  Street,  and  that  summer  we 
could  not  take  auy  enjoyment  out  of  doors.  The  caterpillars  were 
very  thick.  We  destroyed  very  many  of  them,  but  it  seemed 
impossible  to  diminish  their  numbers.  They  seemed  to  be  mul- 
tiplying steadily.  A  mere  shake  of  a  tree  would  bring  them  down 
on  one  in  showers.  They  strip  trees  very  quickly. 

Mr.  D.  W.  Daly,  No.  5  Myrtle  Street,  makes  the  follow- 
ing statement :  — 

I  moved  here  in  1884,  and  the  next  year  got  quite  a  crop  of 
apples.  I  have  three  apple  trees  and  a  crab  apple.  In  1886  the 
gypsy-moth  caterpillars  appeared  for  the  first  time  in  any  consider- 
able numbers  in  my  yard.  Nobody  knew  what  they  were.  There 
were  more  of  them  farther  down  the  street.  In  1887  they  came  in 
droves,  and  before  June  17  they  had  my  trees  stripped  as  clean  as 
in  December.  After  stripping  the  apple  trees,  they  stripped  a 
Sheldon  pear  tree  as  clean  as  the  others.  From  1887  to  1890, 
inclusive,  I  got  no  fruit.  The  caterpillars  worked  some  little  havoc 
on  the  lilacs.  I  was  more  fortunate  than  some  others,  whose  trees 
were  killed.  I  spent  much  time  in  killing  caterpillars.  I  used  to 


10  THE   GYPSY   MOTH. 

sweep  them  off  the  side  of  the  house  and  get  dustpanfuls  of  them. 
At  night  time  we  could  hear  the  caterpillars  eating  in  the  trees  and 
their  excrement  dropping  to  the  ground.  In  the  morning  the  walk 
would  be  covered  with  the  latter.  I  inked  my  trees  in  1888  and 
kept  them  out  of  the  trees  to  some  extent,  but  not  wholly,  for 
some  of  them  blew  into  the  trees,  and  they  also  got  into  them  from 
the  house.  In  1887  I  used  to  sweep  them  off  in  solid  masses  from 
the  tree  trunks.  They  used  to  get  on  the  washing  and  stain  it. 
Two  of  my  apple  trees  since  that  time  have  never  been  the  same 
as  regards  fruit-bearing  qualities.  I  do  not  think  I  saw  six  cater- 
pillars all  last  summer. 

THE  OUTBREAK  OF  1889. 

During  the  years  from  1869  to  1889,  while  the  original 
colony;  of  the  moths  was  increasing  and  extending  its  terri- 
tory at  Glenwood,  stragglers  therefrom  were  constantly 
scattering  abroad  to  form  new  colonies.  Later  these  joined 
with  the  parent  swarm  in  forming  the  multitude  which  spread 
over  the  town.  No  particular  attention  was  paid,  during 
these  years,  to  the  moths  which  appeared  here  and  there,  for 
it  must  be  borne  in  mind  that  the  identity  of  the  insect  had 
been  lost,  and  it  was  not  generally  known  that  there  was  a 
new  insect  in  the  land.  The  introduction  of  dispar  by 
Trouvelot  was  forgotten  or  unknown,  and  wherever  shade 
or  fruit  trees  were  defoliated,  the  damage  was  placed  to  the 
account  of  such  old  and  well-known  pests  as  the  canker-worm 
or  the  tent  caterpillar. 

Gen.  S.  C.  Lawrence,  the  first  mayor  of  Medford,  who 
lives  on  Rural  Avenue,  a  mile  and  a  half  to  the  west  of 
Myrtle  Street,  testifying  in  1893  at  the  hearing  before  the 
legislative  committee  on  Finance,  said :  — 

I  helped  fight  it  [the  moth]  for  years  before  the  appointment  of 
the  commission,  not  knowing  really  what  it  was. 

Mr.  John  Stetson,  living  a  mile  to  the  west  of  Myrtle 
Street,  who  in  1889  sent  specimens  of  the  insect  to  the  Hatch 
Experiment  Station  at  Amherst  for  identification,  said :  — 

I  discovered  them  in  1 888  on  a  quince  bush.  I  noticed  one  day 
that  the  leaves  were  all  off  from  this  bush.  I  examined  it,  and 
found  there  were  worms  there  clustered  on  the  limbs. 


ITS   OUTBREAK  IN   1889.  11 

At  last  a  season  arrived,  that  of  1889,  when  the  moths 
became  so  abundant  in  Glenwood  and  in  some  other  parts  of 
Medford,  and  the  consequent  destruction  of  foliage  so  com- 
plete, that  the  food  supply  gave  out.  Armies  of  "  worms" 
suddenly  appeared  in  localities  where  they  had  never  before 
been  noticed,  and  seemed  about  to  destroy  every  green  thing. 
The  growing  caterpillars  which  had  devoured  the  foliage  in  the 
wooded  land  around  Glenwood,  being  checked  on  the  south 
by  the  salt  marsh,  moved  east,  west  and  north.  They  re- 
inforced those  in  the  yards  and  orchards  along  Myrtle  Street, 
where  most  of  the  foliage  had  already  been  destroyed.  The 
supply  of  food  there  being  at  once  exhausted,  the  caterpillars 
marched  from  yard  to  yard  and  from  tree  to  tree,  their  num- 
bers constantly  augmented  by  those  they  met,  which  in  quick 
succession  were  also  forced  by  lack  of  food  to  join  the  hurry- 
ing host.  Their  enforced  movements  from  tree  to  tree,  from 
yard  to  yard,  and  from  one  street  to  another,  in  search  of 
food,  in  the  summer  of  1889,  are  well  described  by  the  in- 
habitants. It  will  be  seen  that  there  was  no  general  migra- 
tion in  any  one  direction.  The  movements  were  local,  and 
were  directed  mostly  from  those  points  where  the  foliage  had 
been  entirely  destroyed  toward  others  where  some  still  re- 
mained. Such  migrations  had  before  been  noticed  in  Glen- 
wood whenever  the  foliage  had  been  nearly  all  devoured. 
Said  Mrs.  Belcher :  — 

My  sister  cried  out  one  day,  "  They  [the  caterpillars]  are  march- 
ing up  the  street."  I  went  to  the  front  door,  and  sure  enough,  the 
street  was  black  with  them,  coming  across  from  my  neighbor's,  Mrs. 
Clifford's,  and  heading  straight  for  our  yard.  They  had  stripped 
her  trees,  but  our  trees  at  that  time  were  only  partially  eaten. 

Mrs.  R.  Tuttle,  22  Myrtle  Street,  writes :  — 

As  fast  as  we  gathered  them,  others  would  take  their  places. 
They  seemed  to  come  just  like  a  flock  of  sheep. 

Mrs.  I.  W.  Hamlin,  corner  Myrtle  and  Spring  streets, 
said :  — 

Our  yard  was  overrun  with  caterpillars.  .  .  .  When  they  got 
their  growth  these  caterpillars  were  bigger  than  your  little  finger, 


12  THE   GYPSY  MOTH. 

and  would  crawl  very  fast.     It  seemed  as  if  they  could  go  from 
here  to  Park  Street  in  half  an  hour. 

Park  Street,  by  reason  of  its  nearness  to  Glenwood,  soon 
became  infested  by  the  moth.  Mr.  F.  M.  Goodwin,  living 
at  the  corner  of  Park  and  Washington  streets,  testifies  inter- 
estingly to  this :  — 

Some  years  ago  I  saw  the  eggs  of  the  gypsy  moth  plastered 
thickly  on  the  bark  of  a  willow  tree  on  Spring  Street.  A  great 
many  millers  were  laying  their  eggs  there.  The  moths  later  worked 
towards  Park  Street,  and  my  neighbor's  apple  trees  across  the  street 
were  stripped  clean,  leaving  the  young  apples  hanging  on  the  bare 
limbs.  They  crossed  from  this  yard  to  mine,  and  I  killed  pecks 
of  them.  .  .  .  The  caterpillars  came  into  my  yard  by  night.  I 
killed  what  I  could  during  the  day,  and  the  next  morning  I  would 
find  them  as  thick  as  ever. 

While  the  moths  were  thus  travelling  to  the  west  from 
Glenwood  towards  Medford  Square,  others  were  moving  in 
all  directions  from  places  where  they  had  become  established 
in  former  years.  They  appeared  in  great  numbers  on  Cross 
Street,  at  the  residence  of  Mr.  F.  T.  Spinney,  Medford's 
postmaster,  and  crossed  to  the  east  side  of  the  street.  Their 
movements  there  are  recorded  in  the  words  of  people  whose 
trees  and  gardens  suffered.  Said  Mrs.  Spinney  :  — 

I  lived  on  Cross  Street  in  1889.  In  June  of  that  year  I  was  out 
of  town  for  three  days.  When  I  went  away  the  trees  in  our  yard 
were  in  splendid  condition,  and  there  was  not  a  sign  of  insect 
devastation  upon  them.  When  I  returned  there  was  scarcely  a 
leaf  upon  the  trees.  The  gypsy-moth  caterpillars  were  over 
everything. 

Three  other  residents  of  this  neighborhood  speak  as  fol- 
lows :  — 

In  1889  the  caterpillars  of  the  gypsy  moth  appeared  at  Spinney's 
place  on  Cross  Street,  and  after  stripping  the  trees  there  started 
across  the  street.  It  was  about  five  o'clock  one  evening  that  they 
started  across  in  a  great  flock,  and  they  left  a  plain  path  across 
the  road.  They  struck  into  the  first  apple  tree  in  our  yard,  and 
the  next  morning  I  took  four  quarts  of  caterpillars  off  of  one  limb. 
(D.  M.  Richardson,  then  living  at  8£  Cross  Street.) 


PLATE  IV.      View  of  Salem  Street,  near  corner  of  Fulton  Street,  Medford, 

showing  elm  trees  which  were  defoliated  in  1889  by  the  gypsy 

moth.    Prom  a  photograph  taken  in  October,  1895. 


LOCAL   OUTBREAKS.  13 

The  caterpillars  would  travel  on  the  fences  in  droves,  and  we 
could  not  go  out  of  doors  without  getting  them  all  over  us.  ... 
When  the  caterpillars  had  cleaned  out  Mrs.  Spinney's  trees,  they 
started  across  the  street  in  droves  for  the  orchards  on  the  other 
side,  and  the  next  morning  you  could  see  the  path  which  they  had 
made  across  the  street.  (Mrs.  W.  H.  Snowdon,  7  Cross  Street.) 

At  this  time  (summer  of  1889)  they  were  crossing  from  Mr. 
Spinney's  by  multitudes  into  yards  on  the  other  side  of  the  street. 
It  seemed  but  a  few  hours  after  they  left  Mr.  Spinney's  before 
they  were  all  through  my  trees.  They  came  literally  in  droves, 
and  seemed  to  have  a  method  in  their  movements.  (J.  C.  Miller, 
3  Lauriat  Place.) 

Another  outbreak  occurred  on  Vine  Street,  one-half  mile 
from  the  Trouvelot  house.  This  colony  extended  north 
across  Salem  Street  to  Fulton  Street.  Miss  Helen  T.  Wild, 
63  Salem  Street,  writes  :  — 

In  1889  the  apple-trees  in  our  neighborhood  were  attacked  and 
stripped  by  the  gypsy-moth  caterpillars.  They  fed  on  the  apple 
trees  until  there  was  nothing  more  to  eat,  and  then  started  for  the 
elms  on  the  street.  In  the  morning  following  the  night  when  they 
finished  the  apple  trees  they  were  to  be  seen  crossing  the  fence  in 
swarms  in  the  direction  of  the  large  street  elms.  They  were  crawl- 
ing fast,  and  were  plainly  heading  for  the  elms. 

Mrs.  George  Fifield  of  Fulton  Street,  Medford,  first 
noticed  the  caterpillars  at  the  corner  of  Fulton  and  Salem 
streets.  They  were  then  travelling  in  lines  along  the  side- 
walk. Several  of  these  lines  converged  upon  a  large  elm  at 
the  corner  of  the  street,  and  a  constant  stream  of  larvas  was 
ascending  the  trunk.  A  day  or  two  later  all  the  trees  in  the 
neighborhood  were  stripped,  and  in  going  toward  Glen  wood 
she  found  the  same  condition  everywhere. 

Mr.  J.  O.  Goodwin,  writing  in  the  Medford  "Mercury" 
in  1890,  describes  the  movements  of  the  caterpillars  in  his 
neighborhood  on  South  Street :  — 

After  devastating  my  neighbor's  trees,  they  marched  in  myriads 
for  my  premises,  fairly  covering  the  fences,  houses,  out-buildings, 
grass  land,  currant  bushes  and  concrete  driveways  with  their  troop- 
ing battalions.  .  .  .  The  number  of  worms  cultivated  on  the  three 


14  THE   GYPSY  MOTH. 

or  four  worthless  trees  on  the  premises  adjacent  to  my  own  is 
astonishing  ;  numbers  fail  to  convey  an  adequate  idea.  The  earth 
seemed  to  be  covered  with  them. 

In  June,  1889,  there  were  similar  local  outbreaks  over  a 
tract  extending  as  far  as  West  Medford,  two  miles  to  the 
westward,  and  to  Edgeworth  in  Maiden,  a  mile  to  the  east. 

THE  SWARMING  CATERPILLARS  BECOME  A  SERIOUS  NUISANCE. 
The  number  of  caterpillars  that  swarmed  over  certain 
sections  of  the  town  during  the  latter  part  of  June  and  most 
of  July,  1889,  is  almost  beyond  belief.  Prominent  citizens 
have  testified  that  the  "  worms  "  were  so  numerous  that  one 
could  slide  on  the  crushed  bodies  on  the  sidewalks  ;  and  that 
they  crowded  each  other  off  the  trees  and  gathered  in  masses 
on  the  ground,  fences  and  houses,  entering  windows,  destroy- 
ing flowering  plants  in  the  houses,  and  even  appearing  in  the 
chambers  at  night.  The  huge,  hairy,  full-grown  caterpillars 
were  constantly  dropping  upon  people  on  the  sidewalks 
beneath  the  trees,  while  the  smaller  larvae,  hanging  by  in- 
visible threads,  were  swept  into  the  eyes  and  upon  the  faces 
and  necks  of  passers.  The  myriads  that  were  crushed  under 
foot  on  the  sidewalks  of  the  village  gave  the  streets  a  filthy 
and  unclean  appearance .  Ladies  passing  along  certain  streets 
could  hardly  avoid  having  their  clothing  soiled,  and  were 
obliged  to  shake  the  caterpillars  from  their  skirts.  Clothes 
hanging  upon  the  line  were  stained  by  the  larvse  which 
dropped  or  blew  upon  them  from  trees  or  buildings.  In 
the  warm,  still  summer  nights  a  sickening  odor  arose  from 
the  masses  of  caterpillars  and  pupse  in  the  woods  and  orchards, 
and  a  constant  shower  of  excrement  fell  from  the  trees.  The 
presence  of  this  horde  of  gypsy-moth  larvae  had  become  a 
serious  nuisance,  and  was  fast  assuming  the  aspect  of  a  plague. 
The  condition  of  affairs  at  this  time  is  best  shown  by  the 
following  extracts  from  statements  of  residents  :  — 

The  caterpillars  were  worst  in  1887, 1888  and  1889.  In  the  sum- 
mer of  those  years  a  good  portion  of  my  time  was  occupied  in  fight- 
ing the  pest.  The  two  large  elms  in  front  of  our  house  were  full 
of  caterpillars,  and  had  not  a  perfect  leaf.  In  the  night-time  the 
noise  of  the  worms  eating  in  the  trees  sounded  like  two  sticks 


THE   CATERPILLAR  PLAGUE.  15 

grating  against  each  otber.  In  the  months  of  July  and  August  I 
have  gone  out  in  the  morning  and  raked  up  from  under  the  elms 
a  pile  of  leaves  three  or  four  feet  high.  These  leaves  had  been 
cut  off  by  the  caterpillars,  and  usually  there  was  a  worm  on  the 
under-side  of  every  leaf.  I  would  pour  kerosene  over  the  mass 
and  set  it  on  fire,  and  the  squirming  of  the  caterpillars  would 
cause  it  to  rise  up  as  if  it  had  life  of  its  own.  The  caterpillars 
used  to  cover  the  basement  and  clapboards  of  the  house  as  high  as 
the  window  sill.  They  lay  in  a  solid  black  mass.  I  would  scrape 
them  off  into  an  old  dish-pan  holding  about  ten  quarts.  When  it 
was  two-thirds  full  I  poured  kerosene  over  the  mass  of  worms  and 
set  them  on  fire.  I  used  to  do  this  a  number  of  times  a  day.  It 
was  sickening  work.  I  have  used  in  burning  caterpillars  five  gal- 
lons of  kerosene  in  three  days.  I  have  seen  my  fence  black  with 
the  small  caterpillars  when  they  first  hatched  out  in  the  spring.  I 
used  to  kill  them  on  the  fence  by  pouring  scalding  water  on  them. 
The  caterpillars  used  to  be  very  thick  in  the  grass,  and  there 
would  be  one  under  every  fallen  leaf.  On  certain  occasions 
callers  have  had  to  wait  at  the  front  door  until  I  could  sweep  the 
caterpillars  off  the  steps  so  that  they  could  come  in  without  get- 
ting the  worms  on  their  clothing.  (Mrs.  Thomas  F.  Mayo,  25 
Myrtle  Street.) 

On  the  morning  of  the  fourth  of  July,  1889,  my  domestic  and 
myself  went  around  the  whole  of  our  fence  and  gathered  ten  or 
twelve  quarts  of  caterpillars.  A  little  while  afterwards  they  ap- 
peared to  be  just  as  thick  as  ever  on  the  fence.  On  another  occa- 
sion we  gathered  two  quarts  of  eggs  and  caterpillars  from  the 
fence  on  one  side  of  the  yard  only.  ...  It  is  not  easy  to  give 
outsiders  an  idea  of  how  bad  the  caterpillars  were.  If  the  State 
had  not  done  something,  I  honestly  think  we  should  have  had  to 
move  away  from  here.  For  several  summers  the  women  folks  on 
our  street  made  a  regular  business  of  killing  caterpillars.  We  got 
fairly  worn  out  catching  them.  I  have  seen  Mrs.  Mayo,  across 
the  way,  sweep  the  caterpillars  up  in  the  gutter  in  great  piles  and 
burn  them.  .  .  .  Another  of  our  neighbors  had  the  whole  front  of 
her  house  practically  covered  with  caterpillars.  One  could  hardly 
go  out-doors  without  getting  caterpillars  on  the  clothing.  You 
could  see  them  travelling  about.  When  they  were  thickest  we  did 
not  pretend  to  go  out  the  front  door  at  all.  We  had  the  front 
doorsteps  torn  up,  and  found  underneath  a  good  many  nests. 
There  were  thousands  of  eggs  and  caterpillars  under  the  underpin- 
ning of  the  houses.  In  1889  they  got  into  our  cellar,  and  we  had 
it  whitewashed.  When  the  caterpillars  were  very  small  they  would 
get  all  over  the  washing  when  it  was  hung  out.  There  were  no 


16  THE   GYPSY  MOTH. 

trees  very  near,  but  they  would  spin  down  from  somewhere.     (Mrs. 
R.  Tuttle.) 

In  the  summer  of  1889,  while  living  on  Park  Street,  Medford, 
we  were  literally  overrun  with  the  gypsy  moth  caterpillars.  That 
summer  we  could  have  got  the  caterpillars  out  of  the  holes  in  the 
trees  by  pecks.  After  the  caterpillars  ate  all  the  leaves  off  the 
trees,  they  went  down  into  the  grass,  where  they  swarmed.  When 
the  plague  was  the  worst  that  summer,  I  do  not  exaggerate  when 
I  say  that  there  was  not  a  place  on  the  outside  of  the  house  where 
you  could  put  your  hand  without  touching  caterpillars.  They 
crawled  all  over  the  roof  and  upon  the  fence  and  the  plank 
walks.  "We  crushed  them  under  foot  on  the  walks.  We  went 
as  little  as  possible  out  of  the  side  door  which  was  on  the  side 
of  the  house  next  to  the  apple  trees,  because  the  caterpillars 
clustered  so  thickly  on  that  side  of  the  house.  The  front  door 
was  not  quite  so  bad.  We  always  tapped  the  screen  doors  when 
we  opened  them,  and  the  monstrous  great  creatures  would  fall 
down,  but  in  a  minute  or  two  would  crawl  up  the  side  of  the 
house  again.  When  the  caterpillars  were  the  thickest  on  the  trees, 
we  could  plainly  hear  the  noise  of  their  nibbling  at  night  when  all 
was  still.  It  sounded  like  the  pattering  of  very  fine  rain-drops. 
If  we  walked  under  the  trees  we  got  nothing  less  than  a  shower 
bath  of  caterpillars.  We  had  a  hammock  hung  between  the  trees 
that  summer,  but  we'  could  not  use  it  at  all.  The  caterpillars 
spun  down  from  the  trees  by  hundreds,  even  when  they  were  of 
a  large  size.  We  had  tarred  paper  around  the  trees,  but  they 
crawled  up  the  trunks  in  masses  and  went  right  over  the  paper. 
The  bodies  of  those  that  got  stuck  in  the  printers'  ink  served  as  a 
bridge  for  their  brethren.  The  caterpillars  were  so  thick  on  the 
trees  that  they  were  stuck  together  like  cold  macaroni.  A  little 
later  in  the  season  we  saw  literally  thousands  of  moths  fluttering 
in  the  back  yard.  In  the  fall  the  nests  were  stuck  all  over  the 
street  trees.  (J.  P.  Dill,  then  living  on  Park  Street.) 

No  one  who  did  not  see  the  caterpillars  at  that  time  can  form 
any  idea  of  what  a  pest  they  were.  They  got  into  the  strawberry 
bed  (although  they  did  not  eat  the  leaves),  and  I  used  to  go  out 
with  a  dustpan  and  brush  and  sweep  them  up  by  the  panful.  It 
seemed  to  us  absolutely  necessary  to  go  out  daily  and  make  an 
effort  to  at  least  lessen  their  numbers.  We  killed  many  with  boil- 
ing hot  water,  and  would  then  dig  a  hole  and  bury  them,  so  as  to 
prevent  a  stench.  Mr.  Belcher  was  poisoned  by  them.  While 
killing  them  upon  the  trees  they  would  get  upon  his  neck  and  blis- 
ter and  poison  it.  It  was  impossible  to  stay  long  in  the  garden, 
for  they  would  crawl  all  over  one.  We  fought  them  for  two  or 


THE   CATERPILLAK  PLAGUE.  17 

three  years  before  the  commission  took  hold.  When  they  hatched 
out  in  the  spring  our  fence  would  be  one  living  mass.  My  sister 
and  myself  blistered  the  paint  all  off  the  fence  with  the  scalding 
water  that  we  poured  on.  When  they  were  small  it  was  almost 
impossible  to  keep  them  off  one's  person.  It  is  a  fact  that  we  have 
scraped  a  quart  of  eggs  at  a  time  off  the  trees.  We  did  the  best 
we  could  to  keep  them  down,  but  we  could  not  get  them  all,  for 
many  would  hide  away  and  lay  their  eggs.  (Mrs.  William  Belcher.) 

In  1889  the  walks,  trees  and  fences  in  my  yard  and  the  sides  of 
the  house  were  covered  with  caterpillars.  I  used  to  sweep  them 
off  with  a  broom  and  burn  them  with  kerosene,  and  in  half  an  hour 
they  would  be  just  as  bad  as  ever.  There  were  literally  pecks  of 
them.  There  was  not  a  leaf  on  my  trees.  Back  of  the  house  and 
across  the  railroad  track  was  a  large,  tract  of  young-growth  oaks 
and  maples.  They  were  all  stripped.  The  caterpillars  did  not 
leave  a  leaf.  The  trunks  and  branches  were  covered  with  their 
cocoons.  The  cocoons  hung  in  bunches  as  big  as  a  pint  dipper. 
The  stench  in  this  place  was  very  bad.  (Mrs.  S.  J.  Follansbee, 
35  Myrtle  Street.) 

When  the  caterpillars  were  small  they  would  spin  down  on  their 
threads  and  blow  out  into  the  street  or  even  entirely  across  it. 
The  caterpillars  were  a  dirty  pest.  You  could  hardly  go  out  of 
doors  or  sit  down  anywhere  without  getting  them  over  you.  Trees 
were  either  completely  stripped  so  that  not  a  green  thing  was  to 
be  seen  on  them,  or  else  were  eaten  so  that  the  skeletons  of  the 
leaves  only  remained.  The  caterpillars  were  very  numerous  on  a 
large  tree  behind  my  house.  I  have  scraped  them  off  by  the  quart 
on  the  fence  and  shed  adjoining  the  tree.  They  clustered  as 
thickly  as  bees  swarm.  Before  caterpillar  time  we  used  to  see 
bodies  of  trees  plastered  all  over  with  their  egg  clusters.  They 
were  so  thick  on  certain  trees  that  they  reminded  me  of  shells  at 
the  sea-shore.  (J.  H.  Rogers,  17  Spring  Street.) 

I  lived  on  Spring  Street  when  the  caterpillars  were  thickest 
there.  The  place  simply  teemed  with  them,  and  I  used  to  fairly 
dread  going  down  the  street  to  the  station.  It  was  like  running 
a  gantlet.  I  used  to  turn  up  my  coat  collar  and  run  down  the 
middle  of  the  street.  One  morning,  in  particular,  I  remember  that 
I  was  completely  covered  with  caterpillars  inside  my  coat  as  well 
as  out.  The  street  trees  were  completely  stripped  down  to  the 
bark.  .  .  .  The  worst  place  on  Spring  Street  was  at  the  houses  of 
Messrs.  Plunket  and  Harmon.  The  fronts  of  these  houses  were 
black  with  caterpillars,  and  the  sidewalks  were  a  sickening  sight, 
covered  as  they  were  with  the  crushed  bodies  of  the  pest.  (Sylvester 
Lacy,  9  Daisy  Street.) 


18  THE  GYPSY  MOTH. 

They  [the  caterpillars]  were  so  numerous  that  when  they  clus- 
tered on  the  trunks  they  would  lap  over  each  other.  A  neighbor 
gathered  in  one  day  in  my  yard  a  peck  of  caterpillars,  and  poured 
kerosene  over  them  and  set  the  mass  on  fire,  but  many  neverthe- 
less walked  away  from  the  burning  mass.  ...  I  used  to  scoop 
them  off  the  sides  of  the  house  and  the  tree  trunks  with  a  dustpan. 
.  .  .  Their  eating  in  the  trees  sounded  just  like  a  breeze.  Many 
got  into  the  house,  and  we  could  not  open  the  windows.  I  found 
them  in  the  kitchen  and  in  the  bedrooms.  I  used  to  find  them  in 
the  beds  when  I  turned  down  the  blankets.  (Mrs.  Spinney.) 

In  the  summer  of  1889  the  gypsy-moth  caterpillars  attracted  uni- 
versal attention  in  Medford.  They  spread  very  fast  over  the  town. 
I  believe  there  were  enough  that  summer  to  have  caused  the  destruc- 
tion of  all  the  green  leaves  in  town  by  the  following  year,  had 
their  spread  not  been  checked.  During  the  summer  the  caterpillars 
were  found  in  great  numbers  on  South  Street  and  in  the  eastern 
section  of  the  town.  Myrtle,  Park  and  Pleasant  streets  and 
Magoun  Avenue  were  overrun  with  the  pests.  Nobody  knew  what 
these  caterpillars  were  until  they  had  been  identified  in  Amherst. 
They  clustered  on  the  bark  of  the  South  Street  elms  in  multitudes. 
From  the  ground  clear  to  the  tops  of  the  trees  they  lay  thickly  in 
the  rough  bark.  (Ex-Selectman  John  Crowley.) 

The  caterpillars  were  everywhere.  They  would  get  under  the 
doorsteps  and  on  the  window-sills  and  even  into  the  house.  We 
found  them  under  tables  and  even  under  the  pillows.  The  windows 
could  not  be  opened  unless  guarded  by  a  screen.  .  .  .  When  the 
caterpillars  were  full  grown  they  would  herd  in  great  patches  on 
the  trunks.  I  have  seen  the  end  of  Mrs.  Spinney's  house  so  black 
with  caterpillars  that  you  could  hardly  have  told  what  color  the 
paint  was.  In  moth  time  I  have  seen  the  moths  (it  almost  seemed 
by  the  bushel)  crawling  and  fluttering  around  the  bases  of  the 
trees.  (Mrs.  Snowdon.) 

In  1889  the  trees  on  South  Street  were  full  of  caterpillars. 
People  did  not  know  what  they  were  at  first.  The  four  large 
street  elms  in  front  of  my  house  were  covered  with  them.  .  .  . 
The  sidewalk  under  one  elm  was  covered  with  caterpillars  which  ^ 
had  dropped  off.  They  were  so  thick  on  the  tree  that  they  had 
apparently  crowded  each  other  off.  The  front  railing  of  Mr. 
Archibald's  house  on  South  Street  looked  as  if  it  was  covered  with 
mud,  the  caterpillars  were  so  thick  on  it.  (F.  E.  Foster,  20  South 
Street.) 

I  remember  being  at  Judge  Hayes's,  South  Street,  one  evening 
in  the  summer  of  1889.  Mrs.  Hayes  came  in  and  said  that  she 
"  never  saw  such  a  sight"  in  her  life  as  the  caterpillars  presented. 


THE   CATERPILLAR  PLAGUE.  19 

We  went  out  and  found  the  fence  rails  literally  covered  with 
caterpillars.  You  could  not  set  your  foot  down  on  the  walks 
without  crushing  the  worms.  We  took  shingles  and  scraped 
quantities  off  the  trunks  of  the  big  street  elms.  People  used  to 
scrape  them  off  into  piles  and  then  burn  them  with  kerosene. 
(Ex-Selectman  W.  C.  Craig.) 

The  caterpillars  covered  one  side  of  my  house  so  thickly  that  you 
could  not  have  told  what  kind  of  paint  was  on  it.  It  was  impos- 
sible to  keep  them  entirely  out  of  the  house.  The  women  had  to 
shake  their  clothing  when  they  went  into  the  house.  People  used 
to  come  from  other  parts  of  Medford  to  Myrtle  Street  just  to  see 
the  ravages  of  the  insect.  (J.  C.  Clark,  11  Myrtle  Street.) 

The  caterpillars  were  so  thick  in  the  trees  that  you  could  hear 
them  eating.  They  would  get  on  the  fences,  until  they  made  them 
fairly  black.  They  would  crawl  upon  and  into  the  houses.  They 
would  get  inside  somehow,  and  it  was  a  common  thing  to  see  them 
crawling  on  the  table,  and  we  have  even  found  them  on  the  beds. 
They  would  get  under  steps,  stones,  and  into  old  stove-pipes,  old 
cans,  boxes,  in  short,  any  place  which  afforded  a  shelter.  They 
crawled  into  the  cellar  windows.  They  were  so  thick  on  the  street 
trees  that  people  would  walk  out  in  the  middle  of  the  street,  where 
there  were  fewer  dropping  down.  It  is  no  exaggeration  to  say 
that  I  have  raked  quarts  of  caterpillars  off  a  tree.  ...  I  have 
seen  them  crawling  in  great  numbers  on  the  rails  of  the  Medford 
branch  track.  After  a  train  had  gone  along,  the  rails  would  be  all 
green  with  their  crushed  bodies.  (William  Taylor.) 

In  the  old  days,  when  the  caterpillars  were  so  bad,  the  houses 
and  fences  were  blackened  with  them.  We  used  to  sweep  them  off 
into  a  basin  of  kerosene.  As  you  went  up  and  down  the  street 
you  would  see  no  foliage  except  on  pear  trees.  If  you  carried  a 
sunshade  down  the  street,  the  caterpillars  would  get  all  over  it. 
(Miss  R.  A.  McCarty,  26  Myrtle  Street.) 

I  recollect  one  elm  tree  in  particular  on  Park  Street  which  stood 
against  the  fence.  There  was  an  inked  band  around  the  tree,  and 
about  two  quarts  of  gypsy-moth  caterpillars  had  collected  below 
the  band.  Some  of  the  caterpillars  had  got  over  the  band,  and 
they  had  spun  threads  which  served  as  ladders  by  which  the  others 
were  crossing.  (F.  M.  Goodwin.) 

We  could  not  sit  under  the  Porter  apple  tree,  the  caterpillars 
were  so  thick  on  it.  They  swarmed  on  the  ground  at  the  foot  of 
the  Baldwin.  We  poured  boiling  water  on  them.  The  fence  was 
one  mass  of  caterpillars,  and  they  lay  thickly  under  the  clapboards 
and  gutters.  Our  apple  trees  were  stripped  two  years  in  succession. 
(Mrs.  John  Benson,  3  Cross  Street.) 


20  THE  GYPSY  MOTH. 

About  four  to  five  P.M.  they  [the  moths]  flew  about  in  thousands. 
Later  in  the  season  (1889)  their  eggs  could  be  seen  in  clusters  on 
the  stone  walls,  fences,  buildings  and  trees  in  great  numbers,  often 
nearly  covering  such  objects.  (James  Bean,  High  Street.) 

Nothing  too  bad  can  be  said  of  the  caterpillars.  If  you  sat  down 
anywhere  you  would  crush  caterpillars.  If  the  washing  was  hung 
out  under  trees  infested  with  them,  they  would  get  on  and  stain 
the  clean  clothes.  They  were  all  over  the  sidewalks,  and  would 
drop  down  upon  one  from  the  trees.  (Miss  R.  M.  Angelbeek, 
24  Myrtle  Street.) 

In  1888  and  1889  the  gypsy-moth  caterpillars  were  a  terrible 
pest  on  Getting  Street  and  in  that  neighborhood.  In  a  neighbor's 
yard  [Mr.  Rugg's]  they  brushed  off  of  one  apple  tree  at  one  time 
fourteen  quarts  of  caterpillars.  (Almon  Black,  10  Getting  Street.) 

The  elm  trees  in  our  yard  were  badly  eaten  by  the  gypsy-moth 
caterpillars.  The  ribs  of  the  leaves  alone  were  left.  In  the  after- 
noon, when  the  sun  got  low,  the  caterpillars  in  the  trees  would  get 
into  the  sun,  and  you  could  see  the  long  line  of  them  stretching 
away  up  the  tree  trunk.  (Miss  A.B.Bockman,21  Franklin  Street.) 

The  willows  at  the  corner  of  Magoun  Avenue  were  completely 
stripped  for  two  years  in  succession.  The  moths  were  so  thick  at 
one  time  under  the  willows  that  I  have  collected  them  by  the  hand- 
ful and  fed  them  to  my  hens.  (Walter  Sherman,  23  Spring  Street. ) 

In  the  evening  we  could  hear  the  caterpillars  eating  in  the  trees. 
It  sounded  like  the  clipping  of  scissors.  We  kept  the  caterpillars 
down  in  our  yard  as  much  as  possible,  but  it  was  discouraging  to 
see  them  coming  straight  across  the  street  in  droves  to  our  yard. 
They  almost  seemed  to  have  a  concerted  plan  of  action.  (Mrs. 
M.  M.  Ransom,  18  Lawrence  Street.) 

The  trees  of  our  next-door  neighbor,  Mr.  Randall,  suffered  very 
much.  The  caterpillars  got  into  his  evergreens,  and  were  so  thick 
that  they  made  them  look  black.  (Mrs.  Hamlin.) 

In  1889  the  brush  lot  at  the  corner  of  Lawrence  and  Spring 
streets  swarmed  with  gypsy-moth  caterpillars,  and  the  young  oaks 
were  all  stripped  bare.  Our  house  stood  next  to  the  brush  lot. 
The  caterpillars  got  upon  the  outside  in  great  numbers,  and  we 
also  found  many  inside.  (J.  G.  Wheeler,  Daisy  Street.) 

The  outside  of  my  stable  was  literally  black  with  caterpillars  at 
the  time  when  the  gypsy  moth  was  the  thickest  in  this  section.  It 
was  a  disgusting  sight.  (R.  Gibson,  5  Lawrence  Street.) 

The  year  before  the  State  began  fighting  the  gypsy  moth,  I  visited 
an  acre  of  brush  land  in  Glenwood,  where  the  nests  of  the  moth 
were  laid  by  the  hundred  on  stumps,  bush  stalks  and  other  objects. 
This  was  in  the  fall  of  1889.  (J.  Sherman,  76  Riverside  Avenue.) 


THE   CATERPILLAR  PLAGUE.  21 

The  caterpillars  were  thickest  in  Glenwood,  where  in  places  they 
were  like  a  carpet  on  the  ground.  Since  the  State  took  hold  of 
the  matter  the  trees  have  been  in  good  condition,  and  excellent 
work  has  been  done.  (G.  C.  Russell,  11  Washington  Street.) 

The  caterpillars  were  a  sickening  sight  when  they  were  at  their 
thickest.  They  used  to  make  a  living  path,  as  it  were,  from  the 
ground  up  into  a  tree.  (Richard  Pierce,  foreman  of  the  Sparrell 
estate,  No.  90  Main  Street.) 

We  did  what  we  could  in  our  neighborhood  to  fight  the  cater- 
pillars, but  they  were  so  thick  that  one  hated  to  go  out  of  doors 
or  on  the  street.  We  could  plainly  hear  them  at  night  eating  in 
the  trees.  (Miss  Helen  T.  Wild.) 

Many  a  time  I  have  swept  the  caterpillars  off  by  the  dustpanful 
from  the  underpinnings  of  the  house.  (Mrs.  E.  M.  Russell,  then 
living  on  Cross  Street.) 

In  1889  our  apple,  pear  and  crab-apple  trees  were  all  stripped 
by  the  gypsy-moth  caterpillars.  They  either  bore  no  fruit  or  else 
bore  so  late  that  the  frost  destroyed  it.  When  the  caterpillars 
were  small  we  could  see  them  in  the  daytime  spinning  down  from 
the  trees.  At  night  you  could  not  dodge  them,  and  they  would 
get  into  your  neck  and  eyes.  (F.  H.  Haushalter,  42  Myrtle 
Street.) 

A  few  years  ago  the  caterpillars  were  terrible  in  Glenwood. 
You  could  not  go  down  Myrtle  Street  without  getting  your  shoul- 
ders covered.  .  .  .  We  spent  hours  killing  caterpillars,  but  there 
seemed  to  be  two  to  every  one  we  killed.  (A.  P.  Perry,  Myrtle 
Street.) 

I  believe  that,  had  the  State  taken  no  action  in  this  matter,  they 
would  have  increased  to  such  an  extent  that  they  would  have  bred 
a  pestilence  in  our  country.  They  soon  grew  to  the  size  of  your 
finger,  and  the  stench  that  arises  from  them  when  they  are  in  large 
quantities  is  nauseating.  (W.  W.  Fifield  of  Medford,  before  the 
legislative  committee  on  Agriculture,  Feb.  27,  1894.) 

Before  public  measures  were  taken  in  the  matter,  the  foliage 
was  completely  stripped  from  all  the  trees  in  the  eastern  part  of 
our  town,  presenting  an  awful  picture  of  devastation,  and  promis- 
ing in  a  short  time  to  kill  every  tree  and  shrub  and  all  vegetation 
in  any  region  visited  by  the  creatures  ;  which  shows  how  inade- 
quate individual  effort  was  to  cope  with  the  subject.  (J.  O.  Good- 
win, Medford.) 

People  who  wished  to  avoid  the  plague  by  removing  to 
other  towns  or  localities  are  said  to  have  had  some  difficulty 
in  disposing  of  their  homes  on  account  of  the  desolate  appear- 


22  THE  GYPSY  MOTH. 

ance  of  the  surroundings  and  the  disgusting  presence  of  the 
caterpillars. 

The  bad  condition  of  this  section  as  regards  the  gypsy-moth 
plague  was  detrimental  to  real-estate  valuations.  (Mrs.  Mayo.) 

The  gypsy-moth  plague  hurt  property  in  this  section.  Our 
house  was  advertised  for  sale,  and  when  people  came  to  look  at 
the  property  they  were  apt  to  inquire  why  the  leaves  of  the  trees 
in  the  neighborhood  were  so  badly  eaten.  When  we  told  them  it 
was  the  work  of  caterpillars,  they  would  say  that  they  would  not 
live  in  such  a  locality.  (Mrs.  Flinn.) 

The  condition  of  the  Edgeworth  district  of  Maiden  in 
1889  was  similar  to  that  of  Glenwood.  Space  permits  but 
a  few  statements  of  residents  :  — 

The  first  year  that  the  caterpillars  were  Very  bad  was  in  1889. 
They  took  the  leaves  off  the  trees  so  that  they  were  as  bare  as  in 
midwinter.  We  could  not  sit  out  on  the  lawn  a  minute,  for  the 
caterpillars  would  be  all  over  one.  My  son  used  to  climb  a  shade 
tree  in  front  of  the  house  and  shake  the  caterpillars  off.  We 
would  put  a  sheet  underneath,  and  they  would  come  down  in 
showers.  The  top  of  the  fence  was  covered  so  thickly  with  cater- 
pillars that  you  could  not  put  a  pin  between  them.  The  apple 
trees  in  the  yard  next  to  ours  were  stripped.  The  ribs  of  the 
leaves  were  left,  and  they  looked  ghastly.  They  leafed  out  again 
in  June,  but  they  bore  no  fruit.  We  used  to  gather  the  cater- 
pillars in  a  dustpan  and  put  them  in  a  pail.  When  the  pail  was 
full  we  would  dump  them  out  and  burn  them  with  kerosene.  Our 
next-door  neighbor,  Mrs.  Cahill,  used  to  devote  much  time  to 
killing  the  caterpillars.  She  would  sweep  them  off  the  fence  with 
a  broom  and  burn  them.  We  would  see  them  in  droves  on  the 
ground  coming  and  going.  (Mrs.  John  Dowd,  194  West  Street.) 

In  1889  we  were  overran  with  caterpillars.  We  did  not  know 
what  to  make  of  them.  During  that  summer  I  could  not  use  my 
front  door,  they  were  so  thick  around  it.  They  were  as  thick  as 
leaves.  We  had  four  apple  trees,  and  they  were  stripped  entirely 
bare.  A  second  growth  of  leaves  came  out,  but  we  got  no  fruit. 
For  three  years  there  was  not  an  apple  nor  even  a  blossom  on  the 
trees.  We  could  not  have  endured  the  plague,  had  the  State  not 
done  something.  (Mrs.  Daniel  Kelly,  209  West  Street.) 

In  1889  the  caterpillars  were  very  bad.  Every  leaf  was  taken 
off  my  sycamore  tree.  I  used  to  go  out  with  a  hoe  and  scrape  the 
caterpillars  off  the  trunk.  If  I  sat  out  on  my  steps  after  dark 


ITS  DESTRUCTIVENESS.  23 

I  c'ould  bear  them  eating  in  the  tree.  My  other  trees  were  also 
badly  eaten.  (Mrs.  Margaret  Cronin,  corner  of  Oakland  and 
Sheridan  streets.) 

The  trees  in  the  lower  part  of  Edgeworth  were  badly  eaten  by 
the  gypsy- moth  caterpillars  in  1889.  They  were  thick  on  Oakland 
and  Maiden  streets  and  the  Common.  (T.  J.  Neville,  Pearl 
Street.) 

In  1889  we  had  as  many  caterpillars  as  anybody.  You  could 
take  a  knife  and  scrape  them  off  the  trees.  (Mrs.  Margaret  Con- 
nell,  97  Maiden  Street.) 

THE  DESTRUCTIVENESS  OF  THE  MOTH. 
The  caterpillars  devoured  the  foliage  of  nearly  all  species 
of  trees  and  plants  in  the  worst  infested  region.  During  the 
years  when  the  moth  was  most  abundant,  the  destruction  of 
or  injury  to  fruit,  shade  and  forest  trees  and  fruit  and  garden 
crops  was  of  course  greatest.  The  destruction  of  trees  was 
greatest  in  those  localities  where  the  moth  had  been  longest 
abundant,  for,  though  the  smaller  plants  were  often  killed  in 
one  season  as  were  also  the  less  hardy  trees,  those  trees 
which  were  lusty  and  vigorous  would  frequently  withstand 
defoliation  for  two  or  three  successive  years  before  they  finally 
gave  up  their  hold  on  life.  Thus  the  trees  and  gardens  of 
residents  of  Glenwood  suffered  more  in  these  respects  than 
those  of  people  in  other  parts  of  Medford. 

Trees  Killed. 

In  some  cases  where  shade  trees  near  dwellings  were  at- 
tacked they  became  such  a  nuisance  as  a  harboring  place  for 
the  caterpillars  that  they  were  cut  down  while  still  alive,  as 
the  only  practical  means  of  abating  the  nuisance.  Fruit  trees, 
however,  were  generally  allowed  to  stand,  and  a  fight  was 
made  to  save  them,  which  was  in  some  cases  successful,  but 
in  others  all  efforts  to  check  the  ravages  of  the  moth  and 
save  the  trees  were  futile.  They  finally  died,  were  cut  down 
and  the  stumps  rooted  up. 

The  statements  following  are  given  in  the  words  of  people 
whose  trees  suffered  :  — 

We  had  three  apple  trees,  four  pear  trees,  one  plum  tree  and  one 
mountain  ash  killed  by  the  gypsy-moth  caterpillars.  These  trees 


24  THE   GYPSY  MOTH. 

were  stripped  of  their  foliage  in  the  summer  of  1887.  They  began 
to  leaf  out  again  late  in  the  season,  but  were  immediately  stripped. 
The  apple  trees  also  put  forth  a  few  blossoms  at  this  time.  The 
following  year  they  did  not  leaf  out  at  all.  They  all  died,  and  we 
cut  them.  down.  The  apple  trees  were  good-sized  trees.  One  was 
a  spice  greening,  another  a  Porter  and  a  third  an  August  sweeting. 
We  also  cut  down  a  little  locust  tree  which  was  badly  eaten  by 
the  caterpillars,  and  the  limbs  of  which  died.  The  caterpillars 
swarmed  in  a  tall  Norway  spruce  in  our  back  yard.  They  ate 
every  bit  of  foliage  on  this  tree,  so  that  we  had  to  cut  all  the  limbs 
off.  Nothing  but  the  pole  of  this  tree  remains  in  our  yard  to-day. 
This  tree  was  so  full  of  caterpillars  that  when  I  shook  a  limb  with 
a  rake  they  would  fall  off  in  a  shower  and  blacken  the  ground. 
There  were  so  many  of  them  that  it  sounded  like  pebbles  falling. 
In  addition  to  the  trees,  our  currant  bushes  were  stripped  by  the 
pest.  (Mrs.  Mayo,  next-door  neighbor  of  Trouvelot's.) 

The  moths  ruined  me  as  regards  fruit.  They  were  worst  in 
1889.  Their  ravages  caused  me  to  lose  five  nice  apple  trees,  two 
cherry  trees,  one  pear  tree  and  five  plum  trees.  ...  I  had  a  crab- 
apple  tree  that  blossomed  very  full  that  spring,  but  the  caterpillars 
covered  it,  and  it  died.  One  of  the  apple  trees  which  the  cater- 
pillars killed  was  a  beautiful  Hubbardston.  Some  years  I  would 
get  four  barrels  off  of  it  to  put  away.  All  you  will  see  of  it  to- 
day in  my  yard  is  the  stump,  over  which  we  train  nasturtiums. 
The  spring  following  the  ravages  of  the  moth  these  trees  leafed  out 
a  little,  but  not  much,  and  finally  died.  (J.  C.  Clark.) 

In  1889  we  lost  three  apple  trees  because  of  the  caterpillars. 
They  were  stripped  clean,  and  then  leafed  out  and  bloomed  again 
in  September.  The  next  spring  they  leafed  out  a  little,  but  did 
not  bear,  and  finally  died.  (L.  M.  Clifford.) 

In  another  yard  two  large  apple  trees  were  stripped  by  the 
caterpillars,  and  died.  The  way  this  was  brought  about  was  as 
follows :  the  caterpillars  stripped  the  trees  early  in  the  season, 
and,  as  they  continued  their  ravages  for  nearly  the  whole  summer, 
the  trees  had  no  chance  to  recover.  The  next  year  the  trees 
would  leaf  out  and  be  stripped  again,  and  so  on,  until,  unable 
longer  to  withstand  such  treatment,  they  died.  (Almon  Black.) 
Our  next-door  neighbor,  Mrs.  Kelly,  had  a  fine  Baldwin  apple 
tree  which  the  caterpillars  stripped  clean.  They  kept  it  stripped. 
One  year  it  blossomed  twice.  It  leafed  out  and  blossomed  and 
was  stripped,  and  then  leafed  out  and  blossomed  and  was  stripped 
again.  Finally  it  would  leaf  out  and  blossom  once,  perhaps,  and 
then  it  would  leaf  out  but  not  blossom,  and  last  year  only  one 
branch  leafed  out.  The  tree  is  nearly  dead.  This  tree  stood  very 


PLATE  V.     Residence  of  J.  C.  Clark,  No.  11  Myrtle  Street,  Medford.    Th< 

picture  shows  a  portion  of  the  yard  formerly  occupied  by 

fruit  trees  killed  in  1889  by  the  gypsy  moth. 


TREES  KILLED  AND  CUT  DOWN.  25 

near  our  window,  and  as  we  ate  supper  in  the  early  evening  we 
could  distinctly  hear  the  caterpillars  chewing  among  the  leaves. 
In  the  night-time  I  have  frequently  heard  their  "  chip-chip- 
chipping  "  out  in  the  shade  trees  on  the  street.  In  a  yard  adjoin- 
ing ours  there  is  another  apple  tree  which  is  more  than  half  dead 
because  of  the  ravages  of  the  caterpillars.  It-  used  to  bear 
splendid  Baldwins,  but  last  year  there  were  not  more  than  a  dozen 
apples  on  the  tree.  The  caterpillars  used  to  strip  it  twice  a  year 
up  to  two  years  ago,  when  their  numbers  were  greatly  i-educed. 
For  two  years  in  succession  the  caterpillars  stripped  two  maple 
trees  in  front  of  our  house.  They  ate  all  of  the  leaf  except  the 
ribs.  We  had  two  shade  trees  cut  down  which  were  in  a  dying 
condition  because  of  the  ravages  of  the  caterpillars.  This  was 
some  five  or  six  years  ago.  On  Otis  Street  also  we  had  two  trees 
which  we  cut  down  because  the  caterpillars  ate  them  so  badly. 
In  Mrs.  Kelly's  yard  there  was  a  large  balm  of  Gilead  tree  which 
was  cut  down  because  it  was  nothing  more  or  less  than  a  breeding 
place  for  the  gypsy  moth.  The  tree  was  a  sight.  The  trunk  and 
limbs  were  black  with  caterpillars.  The  tree  stood  close  by  Mrs. 
Kelly's  house,  and  you  can  still  see  the  discoloration  under  the 
eaves  where  the  caterpillars  clustered  so  thickly.  Mrs.  Meach, 
across  the  way,  had  a  weeping  willow  cut  down.  (Mrs.  Tuttle.) 

One  of  our  sweet-apple  trees  died  from  the  effects  of  the  strip- 
ping by  the  caterpillars.  The  branches  died  one  by  one,  but  we 
let  it  stand  one  year,  hoping  that  it  would  revive,  but  it  did  not. 
Our  four  Baldwin  apple  trees  bore  good  crops  until  the  caterpillars 
attacked  them.  By  June  you  would  not  see  a  leaf  on  them,  and 
they  would  remain  in  that  leafless  condition  all  summer.  In  the 
fall  of  1892  we  got  our  first  crop  of  apples  in  seven  years.  (Miss 
R.  A.  McCarty.) 

A  young  maple  which  had  been  set  out  on  the  street  in  front  of 
our  house  was  stripped  by  the  caterpillars  and  died.  ...  A  young 
peach  tree  died,  apparently  because  it  was  stripped  by  the  cater- 
pillars. (Mrs.  Flinn.) 

Two  oaks  on  the  street  in  front  of  our  house  were  entirely 
stripped.  The  next  year  they  did  not  leaf  out,  and  were  cut 
down.  (J.  W.  Harlow,  58  Spring  Street.) 

"We  cut  down  two  cherry  trees  in  our  own  yard  because  there 
were  so  many  eggs,  cocoons,  etc.,  in  the  seams  and  holes.  (Mrs. 
Snowdon.) 

I  cut  down  three  tall  poplars  in  front  of  No.  19,  where  I  now 
live,  because  they  were  so  badly  infested.  I  also  cut  down  an 
apple  tree  because  it  attracted  so  many  caterpillars  and  was  so 
badly  eaten.  (William  Taylor.) 


26  THE  GYPSY   MOTH. 

I  had  several  balm  of  Gilead  trees  cut  down  because  they  were 
so  badly  eaten  by  the  caterpillars.  (Walter  Sherman.) 

Our  four  apple  trees  which  we  cut  down  because  of  the  pest 
yielded  the  year  before  eleven  or  twelve  barrels  of  fine  Baldwin 
apples.  (J.  P.  Dill.) 

An  apple  tree  was  stripped  twice,  and  we  had  no  fruit.  The 
caterpillars  so  nearly  killed  the  tree  that  it  has  since  that  time 
borne  very  little.  (Miss  C.  E.  Camp,  28  Myrtle  Street.) 

Fruit,   Garden  Craps  and  Flowering  Plants  Destroyed. 

The  caterpillars  destroyed  not  only  the  foliage  of  trees, 
but  also  fruit  and  vegetables.  The  long  period  of  feeding 
made  it  possible  for  the  larvre  to  secure  a  great  variety  of 
food.  When  the  supply  of  leaves  in  the  trees  fell  short  (and 
oftentimes  before)  they  attacked  the  gardens.  Little  was 
spared  but  the  horse-chestnut  trees  and  the  grass  in  the  fields, 
though  even  these  were  eaten  to  some  extent.  There  was 
evidently  some  choice  exhibited ;  for  instance,  pear  trees 
were  not  so  badly  injured  as  the  apple,  but  eventually  most 
forms  of  vegetable  life  in  the  caterpillars'  path  were  either 
injured  or  entirely  destroyed. 

When  fruit  trees  were  stripped  of  their  leaves,  the  imma- 
ture fruit  either  failed  to  develop  or  dropped  from  the  tree. 
In  some  cases  the  fruit  itself  was  partially  eaten  by  the  vora- 
cious caterpillars.  The  destruction  of  berries  was  often  as 
complete.  Many  vegetables  were  ruined.  Flower  gardens 
were  destroyed,  and  even  greenhouses  were  invaded  and  rose 
bushes  and  other  flowering  plants  eaten.  Our  space  per- 
mits but  a  portion  of  the  evidence  of  such  devastations  in 
Medford :  — 

They  [the  caterpillars]  ate  nearly  everything  green  in  the  yard, 
killing  my  rose  bushes  and  doing  much  damage  to  the  vegetables. 
(Mrs.  Belcher.) 

I  had  quite  a  little  vegetable  garden,  which  was  nearly  ruined  b}T 
the  caterpillars.  They  destroyed  the  cucumbers  and  ate  the  tops 
of  the  tomatoes.  They  also  destroyed  some  flowering  plants. 
(Wm.  B.  Harmon,  5  Spring  Street.) 

They  [the  caterpillars]  even  nibbled  the  young  green  pears,  and 
I  lost  a  good  many  in  that  way.  My  large  cherry  tree,  which  usu- 
ally bears  two  bushels,  was  stripped  clean  for  two  years  running, 
and  I  got  no  fruit.  The  caterpillars  ate  all  the  young  tomato  vines 


GARDEN  CROPS  DESTROYED.  27 

and  injured  my  rose  bushes.  .  .  .  For  three  years  previous  to  1891 
my  Baldwin  apple  tree  bore  no  fruit  on  account  of  the  ravages  of 
the  moth.  It  was  stripped  every  year.  (Mrs.  Follansbee.) 

At  my  place  on  "Woburn  Street  I  had  a  small  bed  of  spinach 
and  dandelions  which  the  caterpillars  completely  destroyed.  My 
tomatoes  suffered  a  like  fate.  (Ex-Selectman  Craig.) 

In  1889  I  had  twenty-seven  hundred  young  carnation  pinks  set 
out  of  doors,  and  the  biggest  part  of  them  were  destroyed  by  the 
caterpillars.  This  was  in  June.  They  were  eaten  off  close  to  the 
ground.  In  1890  the  gypsy  moth  appeared  in  my  greenhouses, 
and  the  foliage  of  the  bushes  in  one  rose  house  was  completely 
eaten  up.  (A.  W.  Crockford,  81  Spring  Street.) 

It  was  almost  impossible  to  have  plants  or  green  things  of  any 
sort.  The  caterpillars  would  eat  anything  that  they  could  get  hold 
of.  The  rose  bushes  were  stripped.  My  mother  plants  yearly 
beans,  peas,  etc.,  but  that  year  we  did  not  get  much  from  them. 
The  parsley  also  was  almost  all  eaten.  (Miss  R.  M.  Angelbeek.) 

The  rose  bushes  were  completely  stripped,  all  the  leaves  and 
blossoms  being  lost.  Despite  the  utmost  efforts  of  two  of  us,  it 
was  impossible  to  keep  the  rose  bushes  free  of  caterpillars.  They 
were  very  fond  of  the  deutzias  in  the  garden,  and  completely 
ruined  them.  (Mrs.  Ransom.) 

They  seemed  particularly  destructive  to  the  Porter  apple  tree. 
The  apples  very  largely  fell  off,  and  the  inside  of  those  that  re- 
mained on  the  tree  was  not  fit  to  eat.  .  .  .  The  caterpillars  ate 
the  leaves  of  a  white  rose  bush  and  a  syringa  in  our  yard,  and  the 
latter  died  from  the  effects  of  the  stripping.  (Mrs.  Benson.) 

Our  vegetable  garden  was  practically  ruined  by  them,  peas, 
beans,  corn,  etc.,  being  eaten.  The  garden  of  our  next-door 
neighbor,  Mr.  Camp,  suffered  a  like  fate.  .  .  .  Our  raspberry 
bushes  were  also  stripped  of  their  leaves.  We  lived  later  on 
Lawrence  Street,  and  here  also  the  caterpillars  were  trouble- 
some. An  umbrella  bush  in  the  yard  was  killed  by  them.  (Mrs. 
Flinn.) 

My  usual  apple  crop  was  from  fifty  to  one  hundred  barrels 
yearly ;  but  the  second  year  of  the  caterpillar  plague  I  did  not 
get  more  than  forty  barrels.  The  third  year  I  do  not  think  I  got 
more  than  thirty  barrels.  (D.  M.  Richardson.) 

After  they  had  eaten  the  foliage  of  trees,  the  caterpillars  would 
devour  almost  any  green  thing.  (J.  N.  French,  7  Lawrence 
Street.) 

They  were  the  most  ravenous  worms  I  ever  saw.  They  would 
eat  almost  everything,  taking  the  apples  and  the  elms  first. 
(John  Cotton,  16  Cotting  Street.) 


28  THE  GYPSY  MOTH. 

The  caterpillars  ate  almost  everything,  feeding  on  small  fruits 
and  shrubbery  as  well  as  the  trees.  (Almon  Black.) 

Our  blackberry  and  raspberry  bushes  were  badly  eaten,  and  we 
got  but  little  fruit  from  them  that  summer  [1890].  (J.  W. 
Harlow. ) 

After  eating  the  foliage  of  the  trees,  the  caterpillars  would  at- 
tack the  vegetables.  (J.  G.  Wheeler.) 

The  caterpillars  even  ate  the  grape-vine  to  some  extent. 
(William  Taylor.) 

How  THE  PEOPLE  FOUGHT  THE  MOTH. 

No  doubt  the  citizens  of  Medford  did  all  that  the  people 
of  any  community  would  have  done  individually  in  fighting 
the  pest.  Many  of  them  owned  their  homes,  and  gave  much 
attention  to  the  care  of  their  grounds.  Each  householder 
had  a  small  lot  of  land,  and  most  of  them  had  gardens  or 
small  orchards  to  protect  from  insect  ravages.  There  were 
many  people  in  a  given  area  each  of  whom  had  an  interest 
in  protecting  his  own  small  portion  of  that  area.  Many  of 
these  people  spent  most  of  their  leisure  time  during  the  sum- 
mer months  in  fighting  the  caterpillars,  killing  great  numbers 
of  them.  The  number  thus  killed  on  Myrtle,  Spring,  Wash- 
ington, Park  and  Cross  streets  during  a  summer  must  have 
checked  considerably  the  increase  of  the  moth.  Many  peo- 
ple banded  the  trunks  of  their  trees  with  tarred  paper,  to 
which  they  applied  tree  ink  as  a  protection  against  the  mi- 
grating worms.  This  was  a  partial  success,  if  the  bands 
were  carefully  watched  and  the  caterpillars  which  gathered 
below  them  killed  in  time  to  prevent  their  crossing  the  bands 
by  mere  force  of  numbers.  A  considerable  part  of  the  fruit 
crop  was  saved  in  some  orchards  in  this  way,  the  tree  ink 
having  the  effect  of  turning  many  caterpillars  away  from 
banded  trees  to  those  left  unbanded.  Yet,  in  spite  of  all 
checks,  the  moths  on  Myrtle  Street  increased  and  spread  so 
as  in  time  to  overwhelm  the  town.  It  is  known  that  people 
there  fought  them  with  fire,  water  and  coal  oil  from  five  to 
eight  years  before  they  became  prevalent  in  other  partsx  of 
Medford. 

Extracts  from  statements  graphically  describing  the  meth- 
ods used  are  given  herewith  :  — 


FOUGHT  BY  THE   PEOPLE.  29 

Many  citizens  scraped  off  all  the  caterpillars  that  they  could, 
and  killed  them.  The  caterpillars  were  scraped  off  in  masses  as 
high  up  as  a  man  could  reach.  Some  people  burned  them  off  by 
means  of  a  rag  soaked  in  kerosene  and  tied  to  a  pole.  (Ex- 
Selectman  Crowley.) 

At  the  time  when  the  gypsy-moth  caterpillars  were  thickest  in 
this  neighborhood  I  used  to  spend  all  my  leisure  time  fighting 
them,  and  then  failed  to  keep  them  down.  .  .  .  "We  used  to  take 
a  can  with  a  little  kerosene  in  the  bottom  and  pick  the  caterpillars 
off  into  it  and  later  bury  them  in  the  ground.  In  a  half-hour  I 
have  picked  a  canful  off  one  apple  tree.  (Mrs.  Ransom.) 

The  caterpillars  were  of  an  enormous  size,  and  would  lie  in  clus- 
ters on  the  tree  trunks.  We  used  to  scrape  them  off  into  a  pail. 
(Mrs.  Charles  A.  Lawrence,  then  living  at  10  Getting  Street.) 

We  used  to  destroy  the  caterpillars  on  the  fences  by  pouring 
scalding  water  on  them.  We  burned  with  kerosene  'those  in  the 
trees.  We  would  go  out  several  times  a  day  and  kill  them.  We 
also  used  to  scrape  them  off  into  cans.  (Mrs.  A.  H.  Plummer, 
14  Lawrence  Street.) 

We  spent  hours  killing  caterpillars  on  them  [street  elms].  We 
would  get  two  quarts  off  at  a  time.  They  were  very  large.  They 
got  into  every  crevice  and  under  every  piece  of  bark.  Our  neigh- 
bor across  the  way,  Mrs.  Turner,  used  to  go  out  with  a  pail  of  hot 
water  and  poke  the  caterpillars  into  it  with  a  stick.  My  son  used 
to  tie  a  rag  soaked  in  kerosene  around  a  pole  and  set  it  on  fire  and 
singe  them -off  the  trunks  of  the  trees.  (F.  E.  Foster.) 

I  put  a  piece  of  stout  paper  about  a  foot  wide  around  the  tree  at 
my  place  for  the  gypsy-moth  larvae  to  go  under.  I  visited  it  a 
number  of  days  later  and  found  the  trunk  of  the  tree  under  the 
paper  to  be  entirely  covered  with  the  insects.  There  were  hun- 
dreds of  them.  A  neighbor,  Mr.  Dutton,  tried  a  similar  experi- 
ment with  a  strip  of  carpet,  with  like  results.  (James  Bean.) 

We  used  to  take  lighted  candles  and  run  them  along  under  the 
fence  rails  and  scorch  the  eggs  there.  (Miss  R.  M.  Angelbeek.) 

I  had  charge  of  this  estate  [Sparrell  estate,  Main  Street],  and  I 
killed  a  great  many  caterpillars  by  brushing  them  off  the  trees  with 
a  broom  and  crushing  them.  After  brushing  them  off  the  trees,  I 
would  wait  half  an  hour  and  then  there  would  be  just  as  many 
again  on  the  trees.  I  could  have  gathered  a  half -bushel  of  cater- 
pillars every  evening  through  their  season.  (Richard  Pierce.) 

I  used  to  burn  them  in  the  trees  with  torches.  .  .  .  We  killed 
them  on  fences  with  boiling  water.  (Mrs.  Spinney.) 

We  used  to  sweep  them  off  into  a  dustpan  and  burn  them,  but  in 
a  short  time  they  would  be  as  thick  as  ever  on  the  ti*ee  again.  .  .  . 


30  THE   GYPSY  MOTH. 

The  next  spring  (1890)  I  found  the  apple  trees  in  my  own  yard 
were  pretty  well  infested  with  nests.  I  had  my  hired  man  scrape 
them  all  off  with  a  putty  knife.  We  collected  them  in  a  dish  and 
burned  them  up  in  the  furnace,  where  they  snapped  and  crackled. 
(J.  E.  Wellington,  Wellington.) 

I  fought  the  caterpillars  in  my  own  yard  by  placing  cloths  in 
the  crotches  and  around  the  trunks  of  the  trees.  The  caterpillars 
collected  in  great  numbers  under  the  cloths,  and  were  then  easily 
destroyed.  (S.  F.  Weston,  11  Fountain  Street.) 

We  had  both  the  steps  and  the  fence  split  up  and  burned,  so 
as  to  deprive  the  pest  of  its  harboring  places.  I  have  frequently 
gathered  half  a  coal-hodful  of  caterpillars  from  the  fence  within  a 
short  space  of  time.  In  twenty  minutes  they  seemed  to  be  just  as 
thick  as  ever.  We  burned  many  pecks  of  them  in  all.  (William 
B.  Harmon.) 

In  the  evening,  after  the  men  had  come  home  from  work,  you 
could  see  fires  in  all  the  yards,  where  they  were  burning  cater- 
pillars. (Mrs.  Fenton.) 

For  four  or  five  years  I  fought  the  gypsy-moth  caterpillars,  as 
did  my  neighbors,  but  could  not  keep  them  down.  ...  By  put- 
ting tarred  paper  around  the  trees  and  keeping  the  printers'  ink 
fresh,  I  succeeded  in  a  measure  in  keeping  the  caterpillars  out  of 
the  trees.  One  tree  which  was  very  full  of  caterpillars  I  sprinkled 
with  the  garden  hose  and  knocked  the  pests  out  of  it.  The  tarred 
paper  kept  them  from  crawling  up  again,  and  they  would  collect 
in  a  mass  below  the  band.  (J.  N.  French.) 

When  the  caterpillars  were  very  small  the  fences  were  black 
with  them.  We  used  to  kill  them  on  the  fences  by  taking  tea- 
kettles and  walking  along  beside  the  rail  and  pouring  boiling  water 
on  the  vermin.  .  .  .  We  would  scrape  them  from  the  tree  trunks 
with  hoes  and  burn  them  with  kerosene.  We  used  to  build  little 
fires  at  the  base  of  a  tree  and  collect  the  eggs  and  burn  them. 
(Mrs.  Snowdon.) 

The  greenhouse  was  full  of  them  [caterpillars].  The  warmth 
caused  them  to  hatch  out  early.  I  destroyed  most  of  them  by 
picking  off  the  leaves  and  burning  them,  and  also  by  spraying 
with  an  emulsion  of  whale-oil  soap,  kerosene  and  ammonia.  (A. 
W.  Crockford.) 

For  six  weeks  a  great  deal  of  our  time  was  devoted  to  killing 
these  caterpillars.  .  .  .  We  would  go  out  in  our  yard  time  after 
time  during  the  day  and  gather  the  caterpillars  in  dishes.  Time 
and  again  I  have  stayed  out  in  the  yard  for  two  hours  at  a  time, 
catching  caterpillars  ;  but  in  half  an  hour  afterwards  they  seemed 
to  be  just  as  thick  again.  (Mrs.  Hainlin.) 


PLATE  VII.     Cherry,  red  cedar  and  yellow  pine  trees  attacked 

by  the  gypsy  moth.    From  a  photograph 

taken  in  Medford. 


INCREASING  ON   NEGLECTED   ESTATES.      31 

During  the  summer  of  which  I  speak  (1889)  my  currant  bushes 
were  also  attacked.  They  were  covered  with  caterpillars,  but  I 
saved  them  by  sprinkling  them  twice  a  day  with  a  solution  of  soap- 
suds and  kerosene.  (J.  C.  Clark.) 

The  Moth  multiplies  on  Neglected  Lands. 
Though  there  were  many  people  who  did  their  utmost  to 
destroy  the  moths,  there  were  others  who  made  little  effort 
in  that  direction.  There  was  waste  land  which  no  one  cared 
for,  and  in  such  places  the  moth  increased  apace,  until  the 
advances  of  the  ravenous  larvae  could  no  longer  be  stayed  by 
individual  effort :  — 

I  think,  if  every  one  had  taken  hold  and  fought  the  moths  in  the 
beginning,  they  might  have  been  stamped  out  right  in  the  place 
where  they  originated.  The  trouble  was  that  some  people  would 
not  do  anything.  Some  people  on  the  street  were  tenants  only, 
and  therefore  took  little  or  no  interest  in  the  condition  of  their 
yards.  I  remember  the  case  of  one  house  which  was  vacant  dur- 
ing one  summer.  The  caterpillars  in  that  yard  were  a  sight. 
Another  neighbor,  not  owning  his  house,  and  not  intending  to 
stay  there,  was  overrun  in  a  like  manner.  (William  Taylor.) 

Other  residents  make  similar  statements  :  — 

A  house  near  by  being  unoccupied,  the  caterpillars  in  the  gar- 
den there  had  full  swing,  there  being  no  one  to  fight  them.  This 
yard  was  a  recruiting  place  for  the  whole  neighborhood.  No 
sooner  would  we  get  our  own  yard  comparatively  free  than  a  lot 
more  would  crawl  around  on  the  fence  from  the  other  yard. 
(Mrs.  Plummer.) 

One  difficulty  in  fighting  the  caterpillars  used  to  be  that  now 
and  then  a  neighbor  would  not  do  anything  to  keep  them  clown  on 
his  own  land.  As  a  consequence,  the  caterpillars,  after  stripping 
this  man's  trees  and  getting  about  three-quarters  grown,  would 
migrate  into  the  other  yards  and  be  even  more  destructive,  their 
voracity  increasing  with  their  size.  (J.  N.  French.) 

The  only  way  I  suffered  was  because  my  neighbors  were  negli- 
gent. The  caterpillars  blew  over  on  to  my  trees.  ...  I  saw  them 
coming  from  my  neighbor's  premises  on  a  concrete  walk  extending 
along  where  my  fruit  trees  grow.  The  walk  was  literally  covered 
with  these  worms  when  they  were  about  the  size  of  your  little 
finger,  so  that  it  appeared  like  a  carpet.  (J.  O.  Goodwin,  before 
the  legislative  committee  on  Agriculture,  Feb.  27,  1894.) 


32  THE  GYPSY  MOTH. 

There  were  some  people  on  Cross  Street  who  used  to  do  nothing 
in  the  way  of  fighting  the  caterpillars,  and  for  that  reason  the  work 
of  individuals  failed  to  cope  with  the  pest.  (Mrs.  Spinney.) 

THE  PLAGUE  BROUGHT  TO  THE  ATTENTION  or  THE  PUBLIC 
AT  LARGE. 

Messrs.  John  Stetson,  W.  C.  Craig,  J.  O.  Goodwin  and 
Dr.  Pearl  Martin,  all  of  Medford,  were  among  the  first  to 
call  public  attention  to  the  ravages  of  the  moth.  Mr.  Stetson 
first  noticed  the  larvre  of  the  moth  in  1888  at  his  place  on 
South  Street,  nearly  a  mile  from  the  Trouvelot  house.  In 
June,  1889,  when  they  began  to  defoliate  the  trees  in  his 
neighborhood,  he  took  a  specimen  for  identification  to  Hon. 
Wm.  K.  Sessions,  secretary  of  the  State  Board  of  Agricult- 
ure. Mr.  Sessions,  being  unable  to  identify  it,  advised 
sending  specimens  to  the  Hatch  Experiment  Station  at 
Amherst.  This  was  done,  and  the  caterpillars  were  received 
at  the  station  June  27.  Professor  Fernald,  the  entomologist 
of  the  station,  was  absent  at  that  time  in  Europe,  and  no  one 
at  the  station  immediately  recognized  the  species.  After  a 
thorough  search  through  American  entomological  literature, 
the  conclusion  was  reached  that  the  insect  was  foreign. 
Recourse  was  then  had  to  European  works  in  the  library  of 
the  entomologist,  and  after  a  slight  search  through  the 
authorities,  Mrs.  Fernald  and  her  son,  Dr.  H.  T.  Fernald, 
identified  the  caterpillars  as  those  of  Ocneria  dispar,  known 
in  England  as  the  "gypsy  moth,"  in  Germany  as  the 
"  sponge  spinner"  or  stem  caterpillar,  and  in  France  as  "  le 
zigzag."  Mr.  Stetson  was  notified  of  the  identification,  and 
information  regarding  the  outbreak  was  immediately  sent  to 
Professor  Fernald.  Later  he  observed  in  Germany  the 
ravages  of  this  insect,  and  consulted  with  European  ento- 
mologists in  regard  to  the  matter.  All  these  authorities 
regarded  the  gypsy  moth  as  a  serious  pest,  and  the  opinion 
was  expressed  that  it  would  become  far  more  destructive 
than  the  potato  beetle,  by  reason  of  the  number  of  its  food 
plants.* 

In  the  mean  time  the  people  of  Medford  were  becoming 
alarmed. 

*  See  Bulletin  of  the  Hatch  Experiment  Station,  November,  1889. 


IT  IS  FOUGHT  BY  THE  TOWN.  33 

The  Medford  "Mercury"  of  June  28,  1889,  contains  this 
item :  — : 

The  army-worm  has  struck  Glenwood  and  Park  Street  gardens, 
stripping  trees  of  their  foliage. 

About  this  time  Mr.  Craig,  then  one  of  the  selectmen  of 
Medford,  became  interested  in  the  outbreak.  The  condition 
of  the  trees  and  gardens  so  alarmed  him  that  he  immediately 
brought  the  matter  to  the  attention  of  the  town  officials.  He 
writes :  — 

In  1889  I  was  connected  with  the  town  government  of  Medford. 
Coming  out  one  day  on  the  train  from  Boston,  I  noticed  that  the 
trees  in  Gleuwood  had  the  appearance  of  having  been  burned.  I 
made  a  remark  to  the  effect  that  the  trees  had  been  burned,  when 
a  lady  said,  "  That  is  the  work  of  the  army- worm."  In  company 
with  Mr.  J.  O.  Goodwin  I  investigated  the  matter,  and  found  that 
the  insects  which  were  preying  on  the  trees  were  not  army- worms. 
Being  a  selectman,  I  conferred  with  the  other  members  of  the 
Board,  but  we  had  nothing  to  do  with  the  trees  on  the  streets  or 
in  the  orchards  of  the  town.  Mr.  Goodwin  and  myself  waited  on 
the  road  commissioners  and  asked  them  to  expend  some  money  in 
stopping  the  ravages  of  the  pests,  which  were  the  gypsy-moth 
caterpillars.  The  commissioners  at  that  time  had  no  money  which 
they  could  expend  for  such  a  purpose,  but  were  in  full  sympathy 
with  the  movement  and  did  all  they  could  to  further  it.  I  saw 
ex-Senator  Boynton,  General  Lawrence,  J.  Henry  Norcross  and 
other  leading  citizens  in  regard  to  the  matter,  and  it  was  agreed 
that  some  action  must  be  taken.  ...  It  was  the  sentiment  that 
the  road  commissioners  should  do  what  they  could  to  stop  the  rav- 
ages of  the  caterpillars. 

The  alarming  condition  of  the  shade  trees  was  considered 
sufficient  cause  for  immediate  action.  At  a  meeting  of  the 
road  commissioners  on  July  1,  it  was  decided  (pending  action 
by  the  town  authorities)  to  put  fresh  ink  on  the  bands  of  the 
trees  on  the  streets  where  the  caterpillars  were  most  numer- 
ous. These  trees,  in  common  with  other  street  trees  in  the 
town,  had  been  banded  earlier  in  the  year  as  a  guard  against 
the  ravages  of  the  canker-worm.  The  inking  of  the  tree 
bands  was  done  the  next  day,  and  at  night  "  it  was  found 


34  THE  GYPSY  MOTH. 

that  thousands  of  the  pests  were  bunched  beneath  the  printers' 
ink"  (Medford  "  Mercury,"  July  5). 

Though  this  protection  of  the  trees  had  the  effect  of  allevi- 
ating the  injury  to  those  protected,  it  hastened  the  diffusion 
of  the  caterpillars  and  drove  them  to  other  plants  and  to 
other  localities  where  trees  were  not  banded,  thus  extending 
the  area  of  the  injury  until  it  included  most  of  the  trees  in 
the  eastern  part  of  the  town.  There  were  some  localities, 
however,  that  escaped  the  general  devastation.  At  a  town 
meeting  held  on  July  15  it  was  voted,  on  petition  of  the 
road  commissioners,  to  appropriate  the  sum  of  three  hundred 
dollars  for  the  care  of  shade  trees.  This  appropriation  of 
three  hundred  dollars  was  in  addition  to  the  usual  appropri- 
ation of  five  hundred  dollars  for  the  care  of  shade  trees  made 
earlier  in  the  year.  It  was  expended  under  the  direction  of 
Dr.  Pearl  Martin,  one  of  the  road  commissioners.  A  num- 
ber of  men  were  employed  in  scraping  off  the  egg  clusters  of 
the  gypsy  moth  from  shade  trees,  chiefly  on  Park  and  Salem 
streets,  where  the  trees  were  badly  infested.  The  eggs  were 
burned  with  kerosene.  In  addition  to  the  work  done  by  the 
town,  much  effort  and  money  were  expended  by  citizens  in 
the  endeavor  to  free  their  premises  of  the  moth. 

Professor  Fernald,  having  meantime  returned  from  Europe, 
visited  Medford  and  viewed  the  infested  district.  Later,  in 
company  with  Hon.  Wm.  E.  Sessions,  secretary  of  the  State 
Board  of  Agriculture,  he  visited  and  inspected  Medford 
again.  These  two  gentlemen  waited  on  Chairman  Wadleigh 
of  the  Board  of  Selectmen,  and  urged  that  the  selectmen  take 
action  to  petition  the  General  Court  for  legislation  authoriz- 
ing the  State  Board  of  Agriculture  to  exterminate  the  cater- 
pillars. This  course  was  approved  by  the  selectmen  at  their 
next  meeting,  October  25  ;  but,  as  the  Legislature  was  not  then 
in  session,  no  immediate  action  was  taken.  In  November  an 
illustrated  bulletin  on  the  gypsy  moth  was  issued  by  Professor 
Fernald  at  the  Hatch  Experiment  Station.  By  authority  of 
the  State  Board  of  Agriculture  and  with  the  co-operation  of 
the  Massachusetts  Society  for  Promoting  Agriculture,  an  edi- 
tion of  forty-five  thousand  copies  was  printed,  and  mailed 
to  tax-payers  in  Medford  and  vicinity.  The  bulletin  was 
printed  in  full  in  the  Medford  "  Mercury"  on  December  6. 


PUBLIC  INTEREST  AROUSED.  35 

The  task  of  destroying  the  eggs,  which  had  been  delegated 
to  the  Medford  road  commissioners,  was  far  greater  than  had 
been  anticipated,  and  the  money  appropriated  was  soon  ex- 
pended, while  only  a  small  part  of  the  eggs  had  been 
destroyed.  While  the  work  was  in  progress  Dr.  Martin  saw 
that  the  moths  were  so  numerous  and  so  widely  distributed 
that  the  town  authorities  could  not  cope  with  them.  At  a 
meeting  of  the  selectmen,  December  10,  he  appeared  in 
behalf  of  the  road  commissioners  and  advised  applying  to 
the  Legislature  for  State  aid.  The  Board  voted  that  the 
clerk  should  communicate  with  Secretary  Sessions  of  the 
State  Board  of  Agriculture  « « in  relation  to  measures  to  be 
taken  to  place  this  matter  properly  before  the  next  Legis- 
lature." 

At  the  next  meeting  of  the  selectmen,  December  17,  a 
communication  was  received  from  the  Hatch  Experiment 
Station,  advising  that  the  Legislature  be  petitioned  for  an 
appropriation  to  exterminate  the  moth.  The  clerk,  reporting 
in  regard  to  his  interview  with  Secretary  Sessions,  recom- 
mended that  petitions  in  favor  of  such  an  appropriation  be 
circulated  in  Medford  and  vicinity  for  presentation  to  the 
Legislature.  Messrs.  Wadleigh  and  Lawrence  were  appointed 
a  committee  to  draw  up  such  petitions.  Mr.  Lawrence  was 
also  appointed  a  committee  to  confer  with  Secretary  Ses- 
sions in  regard  to  preparing  a  bill  to  be  presented  to  the 
Legislature. 

In  December,  Prof.  H.  H.  Goodell,  president  of  the 
Massachusetts  Agricultural  College,  wrote  to  Governor-elect 
Brackett,  urging  that  measures  should  be  taken  by  the  in- 
coming Legislature  to  provide  for  the  extermination  of  the 
gypsy  moth. 

In  his  message  to  the  Legislature  of  1890  Governor 
Brackett  said :  — 


A  new  enemy  is  at  present  threatening  the  agriculture,  not  only 
of  our  own  State,  but  of  the  whole  country.  It  is  the  gypsy  moth, 
said  to  attack  almost  every  variety  of  tree,  as  well  as  the  farm  and 
garden  crops.  The  pest  is  spreading  with  great  rapidity,  and,  if 
its  eradication  is  to  be  attempted,  immediate  measures  are  of  the 
utmost  importance. 


36  THE  GYPSY  MOTH. 

A  petition  for  legislation  for  the  extermination  of  the 
gypsy  moth  was  presented  to  the  Legislature  by  the  select- 
men of  Medford,  Jan.  15,  1890.  Other  towns  joined  in  the 
movement.  On  January  21,  the  selectmen  of  Arlington  pre- 
sented a  petition.  Soon  after,  petitions  were  presented  by 
the  boards  of  selectmen  of  Everett,  Winchester,  Stoneham 
and  Wakefield,  and  by  city  officials  of  Maiden  and  Somer- 
ville.  A  petition  was  presented  from  the  State  Board  of 
Agriculture,  headed  by  President  Goodell  of  the  Agricultural 
College ;  also  one  from  the  Essex  County  Agricultural  So- 
ciety. The  Massachusetts  Horticultural  Society  took  an 
active  part  in  the  movement,  petitioning  the  Legislature  as 
follows :  — 

The  Massachusetts  Horticultural  Society,  recognizing  the  dan- 
gers threatening  the  agricultural  interests  of  the  State  by  the  sud- 
den appearance  in  the  town  of  Medford  of  a  dangerous  insect  pest, 
petitions  the  Legislature,  in  support  of  the  petition  of  the  citizens 
of  Medford  and  adjacent  towns,  for  State  aid  in  stamping  it  out. 

The  joint  standing  committee  on  Agriculture  of  the  Massa- 
chusetts Legislature  visited  Medford  early  in  1890,  and  saw 
the  masses  of  egg  clusters  on  the  trees.*  Public  interest 
having  in  the  mean  time  been  aroused,  an  act  appropriating 
twenty-five  thousand  dollars  "for  the  extermination  of  the 
Ocneria  dispar  or  gypsy  moth"  was  passed. f  This  was  ac- 
complished mainly  through  the  influence  and  untiring  efforts 
of  Mr.  J.  Henry  Norcross  of  Medford,  then  a  member  of  the 
House  of  Representatives,  aided  by  hearty  co-operation  of 
Representatives  from  the  neighboring  towns.  The  act  was 
approved  March  14,  1890,  and  is  here  given  in  full :  — 

[CHAPTER  95.] 

AN  ACT  TO   PROVIDE.  AGAINST  DEPREDATIONS    BY  THE   INSECT   KNOWN 
AS  THE  OCNERIA  DISPAR  OR  GYPSY  MOTH. 

Be  it  enacted,  etc.,  as  follows : 

SECTION  1.  .  The  governor  by  and  with  the  consent  of  the  coun- 
cil is  hereby  authorized  to  appoint  a  commission  of  not  exceeding 
three  suitable  and  discreet  persons,  whose  duty  it  shall  be  to  pro- 

*  "  The  walls  and  almost  every  tree  were  almost  wholly  covered  with  nests." 
(Ex-Senator  Low,  before  the  legislative  committee  on  Agriculture,  Feb.  27,  1894.) 
t  Dispar  has  now  been  referred  to  the  genus  Porthetria. 


PROVIDING  AGAINST  ITS  DEPREDATIONS.    37 

vide  and  carry  into  execution  all  possible  and  reasonable  measures 
to  prevent  the  spreading  and  to  secure  the  extermination  of  the 
ocneria  dispar  or  gypsy  moth  in  this  Commonwealth  ;  and  to  this 
end  said  commission  shall  have  full  authority  to  provide  itself  with 
all  necessary  material  and  appliances  and  to  employ  such  compe- 
tent persons  as  it  shall  deem  needful ;  and  shall  also  have  the  right 
in  the  execution  of  the  purposes  of  this  act  to  enter  upon  the  lands 
of  any  person. 

SECT.  2.  The  owner  of  any  land  so  entered  upon,  who  shall 
suffer  damage  by  such  entry  and  acts  done  thereon  by  said  com- 
mission or  under  its  direction,  may  recover  the  same  of  the  city  or 
town  in  which  the  lands  so  claimed  to  have  been  damaged  are  sit- 
uate, by  action  of  contract;  but  any  benefits  received  by  such 
entry  and  the  acts  done  on  such  lands  in  the  execution  of  the  pur- 
poses of  this  act  shall  be  determined  by  the  court  or  jury  before 
whom  such  action  is  heard,  and  the  amount  thereof  shall  be  applied  in 
reduction  of  said  damages  ;  and  the  Commonwealth  shall  refund  to 
said  city  or  town  one-half  of  the  amount  of  the  damages  recovered. 

SECT.  3.  Said  commission  shall  have  full  authority  to  make 
from  time  to  time  such  rules  and  regulations  in  furtherance  of  the 
purposes  of  this  act  as  it  shall  deem  needful ;  which  rules  and 
regulations  shall  be  published  in  one  or  more  newspapers  published 
in  the  county  of  Suffolk,  and  copies  of  such  rules  and  regulations 
shall  be  posted  in  at  least  three  public  places  in  each  city  or  town 
in  which  said  ocneria  dispar  or  gypsy  moth  shall  be  found  by  such 
commission  to  exist,  and  a  copy  thereof  shall  be  filed  with  the  city 
or  town  clerk  of  each  city  or  town.  Any  person  who  shall  know- 
ingly violate  any  of  the  provisions  thereof  shall  be  punished  for 
each  violation  by  a  fine  not  exceeding  twenty- five  dollars. 

SECT.  4.  Said  commission  shall  keep  a  record  of  its  transac- 
tions and  a  full  account  of  all  its  expenditures,  in  such  form  and 
manner  as  shall  be  prescribed  by  the  governor  and  council,  and 
shall  also  make  return  thereof  to  the  governor  and  council  at  such 
time  or  times  and  in  such  form  as  shall  be  directed  by  the  governor 
and  council.  The  expenses  incurred  under  this  act  shall  be  p'aid 
by  the  Commonwealth,  except  claims  for  damages  by  the  entry 
upon  the  lands  of  any  person  and  acts  done  thereon  by  said  com- 
mission or  by  its  direction,  which  shall  be  paid  as  provided  in  sec- 
tion two  of  this  act. 

SECT.  5.  The  governor  and  council  shall  establish  the  rate  of 
compensation  of  the  commissioners  appointed  under  this  act,  and 
the  governor  may  terminate  their  commissions  at  his  pleasure. 

SECT.  6.  Any  person  who  shall  purposely  resist  or  obstruct 
said  commissioners  or  any  person  or  persons  under  their  emplov, 


38  THE   GYPSY  MOTH. 

while  engaged  in  the  execution  of  the  purposes  of  this  act,  shall 
be  punished  by  a  fine  not  exceeding  twenty-five  dollars  for  each 
offence. 

SECT.  7.  It  shall  be  unlawful  for  any  person  to  knowingly 
bring  the  insect  known  as  the  ocneria  dispar  or  gypsy  rnoth,  or 
its  nests  or  eggs,  within  this  Commonwealth ;  or  for  any  person 
knowingly  to  transport  said  insect,  or  its  nests  or  eggs,  from  any 
town  or  city  to  another  town  or  city  within  this  Commonwealth, 
except  while  engaged  in  and  for  the  purposes  of  destroying  them. 
Any  person  who  shall  offend  against  the  provisions  of  this  section 
of  this  act  shall  be  punished  by  a  fine  not  exceeding  two  hundred 
dollars  or  by  imprisonment  in  the  house  of  correction  not  exceed- 
ing sixty  days,  or  by  both  said  fine  and  imprisonment. 

SECT.  8.  To  carry  out  the  provisions  of  this  act  a  sum  not  ex- 
ceeding twenty-five  thousand  dollars  may  be  expended. 

SECT.  9.  This  act  shall  take  effect  upon  its  passage.  [Ap- 
proved March  14,  1890. 

THE  COMMISSION  OF  1890. 

In  accordance  with  the  provisions  of  the  act  of  March  14, 
Governor  Brackett  appointed  a  salaried  commission,  consist- 
ing of  Warren  W.  Eawson  of  Arlington,  then  a  prominent 
member  of  the  State  Board  of  Agriculture,  Dr.  Pearl 
Martin  of  Medford  and  J.  Howard  Bradley  of  Maiden. 

The  commission  organized  in  Medford,  March  22,  with  the 
choice  of  Mr.  Eawson  as  chairman  and  Mr.  Bradley  as 
secretary  and  general  superintendent.  The  records  show 
that  in  April,  Mr.  Samuel  Henshaw  of  the  Boston  Society  of 
Natural  History  was  appointed  entomologist  to  the  com- 
mission. Headquarters  were  established  in  Medford,  and 
meetings  of  the  commission  were  held  almost  daily  until  the 
last  of  July  and  several  times  per  month  during  the  rest  of 
the*  year. 

The  commission  began  its  labors  by  a  partial  inspection 
of  the  known  infested  district,  for  the  purpose  of  discovering 
and  marking  the  infested  trees,  shrubs  and  other  objects. 
The  infested  trees  were  marked  with  a  red  tag.  The  moth 
was  soon  found  in  many  localities  outside  the  restricted  dis- 
trict to  which  it  was  at  first  supposed  to  be  confined.  This 
district  did  not  exceed  one-half  mile  in  width  and  one  and 
one-half  miles  in  length.  The  inspection  of  1890  justified 


THE   FIRST   COMMISSION.  39 

the  commissioners  in  the  assumption  that  fifty  square  miles 
of  territory  were  then  more  or  less  infested. 

It  soon  became  apparent  that  the  appropriation  of  twenty- 
five  thousand  dollars  would  be  entirely  insumcient  for  the 
needs  of  the  season's  work,  chief  of  which  was  the  expensive 
item  of  spraying.  On  May  9,  in  a  communication  addressed 
to  Governor  Brackett,  the  commission  reported  having  found 
the  infested  territory  "  some  sixteen  times  as  large  as  first 
represented,"  and  asked  for  an  additional  appropriation  of 
twenty-five  thousand  dollars.  This  appropriation  was  made 
by  the  Legislature  and  approved  June  3,  1890.  The  force 
of  employees  was  increased  as  the  season  advanced,  and 
reached  its  maximum  strength  in  June,  eighty-nine  men 
being  employed  from  June  16  to  28. 

During  the  month  of  April  many  eggs  of  the  moth  were 
scraped  from  the  trees  and  destroyed  by  the  employees  of  the 
commission.  Early  in  May  the  spraying  of  infested  trees 
and  foliage  with  Paris  green  was  begun  and  continued  until 
about  the  middle  of  July.  This  was  the  principal  work  of 
the  summer.  Fifteen  teams  were  in  use,  and  spraying  was 
done  in  Medford,  Maiden,  Arlington,  Chelsea  and  Everett. 
The  greatest  amount  of  spraying  was  done  in  the  Glenwood 
and  Wellington  sections  of  Medford  and  the  Edgeworth  dis- 
trict of  Maiden. 

Another  feature  of  the  season's  work  was  the  guarding  of 
highways  leading  out  of  Medford  and  Maiden,  with  the  view 
to  preventing  the  further  dissemination  of  the  moth  by  means 
of  vehicles.  About  a  dozen  special  policemen  were  em- 
ployed ia  this  duty  from  early  in  June  until  the  last  of  July. 
They  were  on  duty  twelve  hours  in  the  day.  Caterpillars  of 
the  moth  were  found  on  many  vehicles  going  out  of  the  in- 
fested district. 

Large  kerosene  torches  were  used  during  the  summer  to 
burn  the  clustering  caterpillars.  Considerable  cutting  and 
burning  of  infested  trees  and  bushes  was  also  done,  the  chief 
work  of  this  sort  being  in  the  badly  infested  woodland  north 
and  south  of  the  railroad  at  Glenwood.  About  twenty  acres 
of  ground  were  thus  cleared. 

In  September  and  October  a  few  men  were  engaged  in 
scraping  eggs  from  the  trees  in  Medford,  Maiden,  Somerville, 


40  THE  GYPSY   MOTH. 

Arlington,  Everett,  Cambridge  and  Chelsea.  In  November 
the  force  was  slightly  increased,  and  an  inspection  was  made 
of  certain  parts  of  the  infested  territory.  The  cavities  of 
some  trees  along  the  highways  were  closed  with  cement. 
On  December  6  all  men  in  the  employ  of  the  commission 
were  discharged,  and  the  field  work  of  1890  closed. 

TJie  Abundance  and  Deslructiveness  of  the  Moth  in  1890. 
Eeferring  to  the  work  of  1890  and  the  numbers  of  the 
moth,  Mr.  E.  J.  Cadey,  an  ex-employee  of  the  commission, 
said :  — 

At  the  time  when  the  commission  first  started  I  saw  the  eggs  of 
the  moth  on  trees  in  such  numbers  that  the  trees  had  a  spongy 
appearance,  and  the  men  who  gathered  them  used  large-sized  pails, 
holding  about  a  peck.  Some  days  we  filled  these  pails  twice  and 
occasionally  three  times.  Especially  was  this  the  case  at  the  "Wel- 
lington willows,  in  Glenwood,  where  the  moths  originated.  The 
walls  of  an  old  shed  were  one  yellow  mass  of  eggs.  Early  in  the 
summer,  previous  to  the  spraying  season,  on  sixteen  acres  of 
woodland  and  brush  on  land  of  Mr.  Pinkert  near  the  Boston  & 
Maine  Railroad,  there  was  not  a  green  leaf  to  be  seen.  We  after- 
wards cut  these  sixteen  acres.  There  were  five  or  six  willows  on 
the  corner  of  Spring  and  Magoun  streets  that  were  so  thickly 
covered  with  pupae  that  the  bark  could  not  be  seen.  In  1890  I  do 
not  think  there  was  a  whole  leaf  in  Medforcl,  and  the  people  com- 
plained of  a  very  disagreeable  stench. 

Mr.  William  Enwright,  who  was  also  employed  by  the 
commission  in  1890,  writes  :  — 

I  was  sent  to  Glenwood  to  the  brick  yards.  Here  I  found  the 
bricks  completely  covered  with  the  caterpillars.  Nearly  opposite 
here,  on  Lawrence  Street,  there  was  an  old  barn  literally  covered 
inside  and  out  with  nests  and  caterpillars.  Trees  were  com- 
pletely stripped.  The  streets  and  sidewalks  were  so  covered  that 
it  was  almost  impossible  to  step  without  crushing  some  of  the 
caterpillars.  In  the  fall  of  the  first  year,  when  we  were  cleaning 
the  nests  from  the  rubbish,  we  used  shovels  to  shovel  them  into 
cans.  You  could  not  walk  in  the  woodland  without  being  covered 
with  caterpillars.  In  1890  Mr.  Bradley  drove  his  horse  through 
the  woods,  and  the  horse's  mane  and  tail  were  covered  with 
caterpillars. 


ITS  RAVAGES  IN  1890.  41 

Mr.  G.  T.  Pierce,  who  was  employed  in  1890,  writes :  — 

When  I  -was  working  at  Dr.  Newton's  place  on  Highland  Ave- 
nue, Somerville,  on  seventeen  or  eighteen  apple  trees  you  could 
not  find  a  leaf  that  had  enough  left  of  it  to  call  it  a  leaf.  Most 
of  them  were  only  a  stub  of  the  midrib.  In  a  large  bunch  of 
willows  at  Wellington,  which  the  old  commission  cut  down  almost 
the  first  thing  they  did,  the  trunks  were  literally  covered  with  egg 
clusters  from  the  ground  up,  so  that  I  doubt  if  you  could  find 
many  places  where  you  could  put  your  hand  on  the  surface  of  the 
tree  without  covering  one  or  more  nests. 

Mr.  C.  S.  Mixter,  an  ex-employee,  testified  as  fol- 
lows :  — 

• 

In  one  place  in  Chelsea  the  nests  were  so  thick  in  1890  that  you 
could  not  put  your  finger  down  without  striking  a  nest.  We 
scraped  the  nests  off.  We  had  several  panfuls. 

Despite  the  great  destruction  of  the  moth  by  the  commis- 
sion during  the  work  of  1890,  the  ravages  of  the  creature 
in  Medford  were  still  serious.  Although  the  injury  wrought 
was  not  as  widespread  as  in  1889,  the  stripping  of  trees 
and  the  consequent  loss  of  fruit  crops  still  continued.  On 
Spring  Street,  in  1890,  the  moths  appear  to  have  been  at 
their  worst.  Mr.  W.  B.  Harmon,  of  No.  55  Spring  Street, 
says :  — 

In  the  summer  of  1890  the  caterpillars  destroyed  all  our  fruit. 
They  attacked  and  stripped  the  apple  trees  first,  and  then  turned 
their  attention  to  the  pear  trees,  which  they  also  stripped.  The 
young  fruit  was  entirely  ruined,  and  we  had  nothing  that  fall. 
The  trees  in  places  were  actually  black  with  the  caterpillars. 
They  would  collect  in  great  bunches,  and  we  would  sweep  them 
off  with  a  broom.  .  .  .  We  could  not  step  out  of  doors,  either 
upon  the  grass  or  the  walk,  without  crushing  the  caterpillars 
under  foot.  Over  our  front  door  the  house  was  black  with  them. 
We  would  clean  them  off  every  morning,  but  in  an  hour  it  would  be 
black  again.  People  could  not  come  in  that  way.  It  is  no  exag- 
geration to  say  that  there  were  pecks  of  the  caterpillars  under  the 
doorsteps  and  on  the  fence.  .  .  .  The  next  lot  to  ours  was  a 
vacant  brush  lot.  It  actually  swarmed  with  caterpillars,  and  they 
caine  from  there  into  our  yard  by  thousands. 


42  THE  GYPSY  MOTH. 

Other  residents  of  the  neighborhood  give  similar  testi- 
mony :  — 

In  1890  we  lived  on  Spring  Street,  and  that  year  the  caterpillars 
seemed  to  be  at  their  worst.  You  could  not  go  along  the  street 
after  dark  without  getting  them  all  over  you.  (Mrs.  Fenton.) 

Four  years  ago  (1890)  I  saw  the  gypsy-moth  caterpillars  by  the 
thousand  on  the  Sherman  lot  on  Spring  Street.  I  never  saw  such 
a  sight.  Their  eggs  were  as  thick  on  the  big  willows  as  spawn  in 
a  fish.  (A.  W.  Crockford.) 

In  1889  the  washing  on  our  clothes  reel  seemed  to  have  a  dingy 
appearance,  and  I  found  tiny  black  worms  on  the  clothes.  These 
would  blow  over  from  the  Myrtle  Street  yard  adjoining.  They 
were  young  gypsy-moth  caterpillars,  although  at  that  time  I  did 
not  know  what  they  were.  The  next  year»they  appeared  in  our 
yard  by  swarms.  The  board  walks  were  completely  covered  with 
them.  It  was  impossible  to  walk  without  crushing  them  under 
foot.  On  going  out  of  doors  they  would  get  on  one's  clothing. 
Our  trees  and  other  green  things  were  stripped  twice  and  leafed 
out  twice.  The  foliage  of  everything  that  was  set  out  in  our  yard 
was  riddled ;  the  woodbine  alone  escaped.  "We  became  dis- 
couraged, and  let  things  go.  The  grape-vine  suffered.  One 
morning  Mr.  Merrill  picked  caterpillars  for  an  hour  and  a  half  off 
one  rose  bush.  The  trunk  of  the  umbrella  tree  in  the  yard  was 
completely  hidden  by  the  mass  of  caterpillars  stuck  together.  I 
scraped  the  caterpillars  off  into  a  tin  can,  but  in  a  short  time  they 
were  just  as  thick  again  on  the  trunk.  Some  of  our  small  fruit 
trees  which  were  stripped  at  that  time  have  not  done  much  since. 
In  that  year  (1890)  if  you  went  down  the  street  with  a  sun  um- 
brella, the  caterpillars  would  drop  down  on  it  just  like  rain. 
(Mrs.  E.  E.  Merrill,  Lawrence  Street.) 

In  1890  the  street  trees  were  badly  injured  by  the  gypsy-moth 
caterpillars.  At  night  in  the  lindens  in  front  of  the  house  there 
was  a  noise  like  the  gentle  falling  of  rain.  This  was  the  noise  of 
the  caterpillars  eating  the  leaves.  (Mrs.  Plummer.) 

In  1890  the  whole  place  was  full  of  gypsy-moth  caterpillars.  I 
think  I  scraped  off  half  a  peck  of  caterpillars  from  the  sills  of  the 
house  and  from  under  the  porch  and  from  off  the  trees.  (E. 
Loeffler,  Lawrence  Street.) 

The  caterpillars  did  much  damage  in  the  Cross  Street 
neighborhood.  Says  Mr.  J.  C.  Miller :  — 

The  next  year  (1890)  all  the  orchards  in  this  section  were  com- 
pletely ravaged,  and  there  was  no  fruit.  The  caterpillars  simply 


ITS  RAVAGES  IN   1890.  43 

swarmed.  I  destroyed  thousands  of  them  by  burning  them  with 
rags  soaked  in  kerosene.  I  spent  many  hours  in  destroying  them, 
but  without  making  any  perceptible  difference  in  their  numbers. 
They  were  over  everything,  and  even  got  into  the  cellars.  Some 
of  my  apple  trees  overhang  my  shop.  In  the  evening  when  the 
caterpillars  were  liveliest  the  noise  of  their  droppings  falling  on 
the  shingles  sounded  like  a  steady  shower.  The  gutter  was  brim- 
ful and  running  over  with  the  droppings. 

Other  sections  of  the  town  were  afflicted  in  like  manner :  — 

In  1890  the  apple  trees  on  Fulton  Street,  Allen  Court  and 
Fountain  Street  were  more  or  less  stripped  by  the  gypsy-moth 
caterpillars.  Some  of  the  apple  trees  were  wholly  denuded  of 
their  foliage,  and  the  crops  in  some  cases  were  lost.  In  some 
cases  the  limbs  of  the  apple  trees  were  killed  by  the  ravages  of 
the  caterpillars.  Even  pear  trees  were  sometimes  badly  eaten, 
and  cherries  also  suffered.  The  leaves  were  completely  destroyed 
on  a  little  German  willow  in  my  yard.  Rose  bushes  were  very 
badly  eaten.  (S.  F.  Weston.) 

The  large  elm  in  front  of  my  house  was  full  of  caterpillars  in 
1890.  The  leaves  were  riddled  and  many  were  cut  off.  We  would 
sweep  up  daily  these  bits  and  fragments  of  leaves  which  fell  from 
the  tree,  but  the  next  day  the  ground  beneath  would  be  littered 
with  them  again.  This  elm  stands  in  front  of  the  piazza,  and 
many  caterpillars  came  from  the  tree  upon  the  house.  They  were 
so  thick  that  we  could  not  sit  out  on  the  piazza  at  all  that  summer. 
When  we  opened  the  front  door  they  would  string  down  all  over 
one.  The  caterpillars  at  one  time  were  so  thick  on  a  fence  on 
Salem  Street  that  I  could  have  run  my  hand  along  the  top  rail  and 
scooped  them  up.  In  this  same  year  a  maple  tree  standing  in 
front  of  my  house  on  Allen  Court  was  badly  eaten  by  the  cater- 
pillars. You  could  hear  them  eating  up  in  the  tree.  (Mrs.  P.  N. 
Ryder,  Salem  Street.) 

The  gypsy-moth  caterpillars  were  very  numerous  in  1890  on  the 
Sparrell  estate,  No.  90  Main  Street.  ...  As  evening  came  on 
you  would  see  them  everywhere  on  the  ground  heading  for  the 
trees.  I  have  heard  the  noise  of  their  feeding  after  dark.  They 
kept  coming  into  my  yard  from  the  yards  of  other  people  who  paid 
less  attention  to  destroying  them.  The  leaves  of  the  trees  were 
just  as  if  they  had  been  scorched.  One  tree  did  not  bear  for 
several  years.  (Richard  Pierce.) 

In  1890  I  saw  the  caterpillars  clustering  in  a  mass  on  the  body 
of  an  elm  tree  on  South  Street.  I  destroyed  a  great  many  of  these 
by  burning.  (John  Hutchins,  16  South  Street.) 


44  THE  GYPSY  MOTH. 

Four  years  ago  (1890)  in  the  yards  on  the  north  side  of  Cotting 
Street  the  gypsy-nioth  caterpillars  stripped  the  trees  bare  of  their 
leaves.  (John  Cotton.) 

In  1890  I  fought  the  pest.  They  came  on  to  my  place  in  mill- 
ions in  April.  The  top  of  my  fence  rail  would  be  covered  with 
gypsy-moth  caterpillars  about  as  small  as  ants.  ...  I  would 
take  a  brush  broom  and  fight  them  perhaps  an  hour  and  a  half.  I 
would  destroy  them  in  the  morning,  and  at  noon  would  find  as 
many  more  and  clean  them  every  one  from  my  premises.  At 
night  I  went  through  the  same  operation.  I  destroyed  undoubt- 
edly millions.  (W.  W.  Fifield,  before  the  legislative  joint  stand- 
ing committee  on  Agriculture.) 

Residents  of  Edgeworth  make  similar  statements  :  — 

The  caterpillars  were  very  thick  on  the  house  in  1890.  When 
I  went  out  of  my  side  door  I  had  to  take  a  broom  and  brush  them 
off  the  platform.  I  killed  quarts  that  summer.  At  the  next  house 
they  were  just  as  bad.  I  swept  them  off  above  the  door  again 
and  again,  and  they  seemed  to  be  back  again  as  thick  as  ever  in 
five  minutes.  An  apple  tree  back  of  the  house  looked  as  'if  the 
leaves  had  all  been  burned.  A  few  blossoms  would  come  out  and 
then  wither  away.  I  saw  the  gypsy-moth  men  burn  the  cater- 
pillars by  the  pailful.  (Mrs.  B.  Wallace,  West  Street,  Edge- 
worth.) 

In  1890  they  were  also  plentiful,  although  not  as  thick  as  in 
1889.  I  got  few  if  any  apples  in  either  year.  The  caterpillars 
were  larger  than  your  little  finger.  They  would  lie  thickly  to- 
gether on  the  trunks  of  the  trees.  In  the  evening  they  were  so 
thick  that  they  would  di'op  down  on  the  steps  from  above  the 
door.  (William  McLaughlin,  107  Oakland  Street.) 


THE  WORK  OF   1891.  45 


THE    WORK    OF    1891. 

Appointment  of  the  Second  Commission. 
Governor  Russell,  having  removed  on  Feb.  15,  1891,  the 
salaried  commission  for  the  extermination  of  the  gypsy  moth, 
appointed  another  commission  which  organized  as  follows : 
Prof.  N.  S.  Shaler  of  Harvard  University,  chairman,  Francis 
H.  Appleton  of  Peabody,  secretary,  both  members  of  the 
State  Board  of  Agriculture,  and  Hon.  Wm.  R.  Sessions, 
secretary  of  that  Board.  These  gentlemen  served  without 
remuneration,  accepting  office  with  the  understanding  that 
legislation  would  be  asked  for  with  reference  to  placing  the 
work  under  the  control  of  the  State  Board  of  Agriculture, 
where  they  believed  it  properly  belonged.  The  new  com- 
missioners, having  received  information  of  their  appoint- 
ment by  the  governor,  lost  no  time  in  obtaining  information 
from  the  best  authorities  in  regard  to  the  possibility  of  ex- 
terminating the  moth  and  the  best  methods  of  procedure. 
They  received  their  commission  on  March  4,  and  the  same 
day  held  a  conference  at  the  office  of  the  State  Board  of  Ag- 
riculture, with  several  eminent  entomologists.  Many  promi- 
nent men  from  the  towns  in  the  region  infested  by  the  gypsy 
moth  were  also  invited  to  attend.  Among  those  present  were 
Professor  Riley,  entomologist  of  the  United  States  Depart- 
ment-of  Agriculture,  Professor  Fernald,  entomologist  of  the 
Hatch  Experiment  Station  and  of  the  Board  of  Agriculture, 
Mr.  Samuel  Scudder  of  Cambridge,  Mayor  Wiggin  of  Maiden, 
Chairman  L.  S.  Gould  of  the  selectmen  of  Melrose,  Select- 
man W.  C.  Craig  of  Medford  and  W.  A.  Pierce  of  Arling- 
ton. The  prevailing  opinion  of  the  entomologists  was  that 
recourse  must  be  had  to  spraying  with  some  of  the  arsenites 
in  order  to  bring  about  the  extermination  of  the  moth.  (See 
Appendix  A  for  a  report  of  the  conference.) 

Preliminary  Arrangements. 

On  March  12  the  commissioners  invited  the  members  of 
the  first  commission  to  a  consultation  at  the  office  of  the 
State  Board  of  Agriculture.  Ex-Commissioners  Rawson  and 


46  THE   GYPSY  MOTH. 

Bradley  met  with  the  commissioners.  They  gave  the  com- 
mission such  information  as  they  possessed  in  regard  to  the 
habits  of  the  moth,  the  methods  used  in  controlling  it  and 
preventing  its  spread,  its  distribution  and  the  extent  of  terri- 
tory infested  by  it.  They  also  outlined  on  a  map  the  territory 
known  by  them  to  be  infested  by  the  moth.  (See  map.) 
The  ' '  director  of  field  work  "  who  was  appointed  on  that  day 
was  present  and  consulted  with  the  commissioners  in  regard 
to  taking  immediate  steps  for  the  eradication  of  the  moth. 

In  view  of  the  conflicting  opinions  expressed  in  regard  to 
the  effectiveness  of  spraying  as  a  means  of  extermination, 
it  was  decided  to  organize  at  once  a  force  of  men,  and  to 
destroy  as  many  of  the  eggs  of  the  gypsy  moth  as  possible 
before  the  time  for  hatching  arrived.  The  director  took  the 
train  at  once  for  Amherst,  and  visited  the  Hatch  Experiment 
Station,  where  two  days  were  spent  in  consultation  with  the 
entomologist,  Prof.  C.  H.  Fernald,  and  in  examining  insecti- 
cide appliances  and  the  literature  germane  to  the  subject. 

It  had  been  proposed  by  the  commissioners  that  the  di- 
rector secure  the  services  of  some  of  the  students  or  gradu- 
ates of  the  Massachusetts  Agricultural  College  as  assistants. 
Through  the  good  offices  of  Professor  Fernald  and  Dr.  H. 
H.  Goodell,  president  of  the  college,  in  advising  the  students, 
several  young  men  were  induced  to  engage  in  the  work 
of  extermination.  Some  of  these  students  had  studied  eco- 
nomic entomology  under  the  guidance  of  the  entomologist, 
and  were  especially  fitted  for  the  work  in  hand.  From  that 
time  Professor  Fernald's  advice  and  assistance  were  always 
freely  sought  by  the  committee  and  director,  and  as  freely 
given.  All  plans  made  were  submitted  to  him  for  approval, 
and  were  only  perfected  after  a  careful  consideration  of  his 
recommendations.  The  students  who  had  been  engaged  were 
released  in  a  few  days  from  their  college  engagements,  and 
on  March  19  nine  of  them  reported  at  the  office  of  the  State 
Board  of  Agriculture  and  received  instructions.  In  the 
mean  time  the  office  and  storehouse,  which  had  been  used  by 
the  first  commission,  had  been  opened,  an  inventory  of  prop- 
erty taken,  and  a  hasty  inspection  made  of  the  infested  region 
by  the  director,  in  company  with  Ex-Commissioner  Bradley. 
A  few  experienced  men  had  also  been  employed. 


THE   WORK  OF   1891.  47 

On  March  20  actual  work  in  the  field  was  begun.  The 
director  and  sixteen  men  visited  the  farm  of  Mr.  Oilman 
Osgood  in  Belmont,  which  was  the  only  locality  in  that  town 
known  by  the  first  commission  to  be  infested.  It  was  then  sup- 
posed that  this  was  an  isolated  moth  colony,  and  an  attempt 
was  made  to  stamp  it  out  by  gathering  the  eggs.*  During 
the  day,  however,  other  colonies  were  found  in  Belmont. 

The  Work  delegated  to  the  Board  of  Agriculture. 
The  commission  of  1891  was  superseded  after  a  few  weeks 
by  the  State  Board  of  Agriculture,  the  act  (chapter  210, 
Acts  of  1891)  placing  the  work  in  the  hands  of  the  Board 
being  approved  April  17.     The  act  follows  :  -r— 

[Acxs  OP  1891,  CHAPTER  210.] 

AN  ACT  TO    PROVIDE  AGAINST    DEPREDATIONS   BY  THE    INSECT  KNOWN 
AS    THE    OCNERIA   DISPAR    OR   GYPSY   MOTH. 

Be  it  enacted,  etc.,  as  follows: 

SECTION  1.  The  state  board  of  agriculture  is  hereby  authorized, 
empowered  and  directed  to  provide  and  carry  into  execution  all 
reasonable  measures  to  prevent  the  spreading  and  to  secure  the 
extermination  of  the  ocneria  dispar  or  gypsy  moth  in  this  Common- 
wealth ;  and  to  this  end  said  board  shall  have  full  authority  to 
provide  all  necessary  material  and  appliances,  and  to  employ  such 
competent  persons,  servants  and  agents  as  it  shall  from  time  to 
time  deem  necessary  in  the  carrying  out  the  purposes  of  this  act ; 
and  said  board  shall  also  have  the  right  itself  or  by  any  persons, 
servants  or  agents  employed  by  it  under  the  provisions  of  this  act 
to  enter  upon  the  lands  of  any  person. 

SECT.  2.  The  owner  of  any  land  so  entered  upon,  who  shall 
suffer  damage  by  such  entry  and  acts  done  thereon  by  said  state 
board  of  agriculture  or  under  its  direction,  may  recover  the  same 
of  the  city  or  town  in  which  the  lands  so  claimed'  to  have  been 
damaged  are  situate,  by  action  of  contract ;  but  any  benefits 
received  by  such  entry  and  the  acts  done  on  such  lands  in  the 
execution  of  the  purposes  of  this  act  shall  be  determined  by  the 
court  or  jury  before  whom  such  action  is  heard,  and  the  amount 
thereof  shall  be  applied  in  reduction  of  said  damages ;  and  the 
Commonwealth  shall  refund  to  said  city  or  town  one-half  of  the 
amount  of  the  damages  recovered. 

*  The  attempt  to  eradicate  the  colony  was  not  at  that  time  successful,  but  was  ac- 
complished later.    The  moths  were  found  that  season  in  many  localities  in  Belmont. 


48  THE   GYPSY  MOTH. 

SECT.  3.  Said  state  board  of  agriculture  shall  have  full 
authority  to  make  from  time  to  time  such  rules  and  regulations  in 
furtherance  of  the  purposes  of  this  act  as  it  shall  deem  needful, 
which  rules  and  regulations  shall  be  published  in  one  or  more 
newspapers  published  in  the  county  of  Suffolk  ;  and  copies  of  such 
rules  and  regulations  shall  be  posted  in  at  least  three  public  places 
in  each  city  or  town  in  which  said  ocneria  dispar  or  gypsy  moth 
shall  be  found  by  said  board  to  exist  and  a  copy  thereof  shall  be 
•filed  with  the  city  clerk  of  each  such  city  and  with  the  town  clerk 
of  each  such  town ;  and  any  person  who  shall  knowingly  violate 
any  of  the  provisions  thereof  shall  be  punished  for  each  violation 
by  a  fine  not  exceeding  twenty-five  dollars. 

SECT.  4.  Said  state  board  of  agriculture  shall  keep  a  record  of 
its  transactions  and  a  full  account  of  all  its  expenditures  under  this 
act,  and  shall  by  its  chairman  or  secretary  make  report  thereof, 
with  such  recommendations  and  suggestions  as  said  board  shall 
deem  necessary,  on  or  before  the  fourth  Wednesday  in  January,  to 
the  general  court. 

SECT.  5.  Said  state  board  of  agriculture  shall  establish  the  rate 
of  compensation  of  any  persons,  servants  or  agents  employed  by 
it  under  this  act. 

SECT.  6.  Any  person  who  shall  purposely  resist  or  obstruct  said 
state  board  of  agriculture,  or  any  persons,  servants  or  agents  em- 
ployed by  it  under  the  provisions  of  this  act,  while  engaged  in  the 
execution  of  the  purposes  of  this  act,  shall  be  punished  by  a  fine 
not  exceeding  twenty-five  dollars  for  each  offence. 

SECT.  7.  It  shall  be  unlawful  for  any  person  knowingly  to  bring 
the  insect  known  as  the  ocneria  dispar  or  gypsy  moth,  or  its  nests 
or  eggs,  within  this  Commonwealth ;  or  for  any  person  knowingly 
to  transport  said  insect,  or  its  nests  or  eggs,  from  any  town  or  city 
to  another  town  or  city  within  this  Commonwealth.  Any  person 
who  shall  offend  against  the  provisions  of  this  section  shall  be  pun- 
ished by  a  fine  not  exceeding  two  hundred  dollars  or  by  imprison- 
ment in  the  house  of  correction  not  exceeding  sixty  days,  or  by 
both  such  fine  and  imprisonment. 

SECT.  8.  The  said  state  board  of  agriculture  may  exercise  all 
the  duties  and  powers  herein  conferred  upon  said  board,  by  and 
through  its  secretary  and  such  members  of  said  board  as  it  may 
designate  and  appoint  to  have  in  charge,  in  conjunction  with  its 
secretary,  the  execution  of  the  purposes  of  this  act. 

SECT.  9.  All  moneys  heretofore  appropriated  or  authorized  to 
be  expended  under  the  provisions  of  chapters  ninety-five  and  one 
hundred  and  fifty-seven  of  the  acts  of  the  year  eighteen  hundred 
and  ninety  or  by  any  other  act,  and  not  heretofore  expended,  are 


A  NEW   STATUTE.  49 

hereby  appropriated  and  authorized  to  be  expended  by  the  said 
board  in  carrying  out  the  purposes  of  this  act. 

SECT.  10.  All  the  property  acquired  and  records  kept  under  the 
provisions  of  said  chapter  ninety-five  of  the  acts  of  the  year  eigh- 
teen hundred  and  ninety  shall  be  delivered  into  the  custody  of  said 
board,  and  said  board  is  authorized  to  take,  receive  and  use  the 
same  for  the  purposes  of  this  act. 

SECT.  11.  Chapter  ninety-five  of  the  acts  of  the  year  eighteen 
hundred  and  ninety  is  hereby  repealed,  but  all  claims  for  damages 
under  said  chapter  ninety-five  for  entry  upon  and  acts  done  on 
the  lands  of  any  person  may  be  prosecuted,  as  therein  provided, 
against  the  city  or  town  wherein  the  lands  entered  upon  are  situate, 
and  the  damages  shall  be  ascertained  and  one-half  of  the  amount 
thereof  recovered  against  any  city  or  town  shall  be  refunded  to 
such  city  or  town  as  provided  in  said  chapter  ninety-five.  [Ap- 
proved April  17,  1891. 

A  special  meeting  of  the  Board  of  Agriculture  was  held 
on  April  28,  and  Messrs.  Sessions,  Shaler  and  Appleton 
were  appointed  a  committee  in  accordance  with  the  provi- 
sions of  section  8  of  the  act. 

This  committee  organized  on  May  19,  with  the  choice  of 
Mr.  Sessions  as  chairman  and  secretary.  The  committee 
continued  the  work  which  it  had  begun  as  a  commission, 
confirming  the  appointment  of  the  field  director,  and  directed 
that  the  work  being  done  in  the  field  should  be  continued. 
A  code  of  rules  and  regulations  for  the  public  was  adopted. 
(See  Appendix  B.)  At  the  time  of  appointment  of  the 
second  commission  there  remained  unexpended  of  the  ap- 
propriation of  1890  the  sum  of  $24,460.68.  On  May  19 
$11,003.22  only  remained.  On  June  30  an  additional  ap- 
propriation of  $50,000  was  made  by  the  Legislature. 

Mapping  the  Infested  Region. 

In  apportioning  the  territory  to  different  inspectors,  it  was 
found  necessary  to  make  a  hasty  survey  of  the  field  and  to 
plat  it  on  maps  of  the  towns  known  to  be  infested  and  those 
contiguous  to  them.  These  maps  were  divided  into  sections 
of  such  size  as  could  be  conveniently  carried  by  the  men 
engaged  in  field  work.  For  convenience  these  sections 
were  so  drawn  as  to  be  bounded  by  town  lines,  streets  and 


50  THE   GYPSY  MOTH. 

railways,  or  by  natural  bounds,  such  as  streams  and  lakes. 
Each  map  was  accompanied  by  a  written  description  of  the 
boundaries  of  the  section  which  it  represented.  The  work 
was  done,  under  the  supervision  of  the  director,  by  Mr. 
J.  O.  Goodwin  of  Medford,  an  experienced  engineer,  well 
acquainted  with  the  topography  of  the  region.  It  was  in- 
tended so  to  divide  the  region  that  each  inspector  or  foreman 
could  be  held  responsible  for  a  certain  tract  or  section  with 
definite  and  well-marked  boundaries.  Each  section  in  each 
town  was  numbered.  Each  inspector,  on  entering  the  field, 
was  required  to  run  the  boundaries  of  the  section  allotted  to 
him,  and  mark  the  section  number  prominently  with  white 
paint  on  fixed  objects  at  each  angle  of  the  boundary.  To 
avoid  any  possible  confusion  of  lines,  each  inspector  was 
also  required  to  "  blaze  "  or  mark  the  line  with  white  paint 
wherever  it  was  not  otherwise  easily  distinguishable.  When 
this  system  was  extended  into  the  towns  farthest  from  the 
infested  centre,  it  was  not  found  necessary  to  divide  such 
towns  into  sections  on  account  of  the  comparatively  small 
number  of  moth  colonies  found  in  them.  They  were  treated, 
therefore,  as  sections,  and  an  inspector  with  a  gang  of  men 
was  placed  in  charge  of  each.  If,  however,  it  was  found,  on 
close  inspection,  that  a  town  that  had  not  been  "  sectioned" 
was  badly  infested,  and  would  require  several  gangs  of  men, 
it  was  then  "  sectioned."  Each  inspector  was  required  occa- 
sionally to  sketch  maps ;  also  to  locate  and  mark  infested 
localities  on  section  maps,  and  to  make  such  additions  to  the 
maps  as  were  from  time  to  time  necessitated  by  the  con- 
struction of  new  streets  or  railways  in  the  infested  towns. 

Organization  and  Instruction  of  the  Field  Force. 

Whenever  suitable  men  could  be  found  they  were  added 
to  the  force.  Some  of  the  most  capable  men  of  the  force 
of  1890  were  re-employed.  Others,  whose  previous  expe- 
rience in  field  study  in  entomology  or  kindred  sciences  had 
fitted  them  for  careful  observation,  were  engaged  and  trained 
to  act  as  inspectors. 

When  field  operations  were  commenced  the  eggs  of  the 
moth  were  the  only  living  form  of  the  pest.  The  men 
were  taught  how  to  recognize  and  destroy  them,  and  to 


THE  INSTRUCTION  OF  EMPLOYEES.          51 

distinguish  them  from  those  of  native  moths.  They  were 
taught  to  observe  all  evidences  of  the  presence  of  the  gypsy 
moth,  and  were  requested  to  secure  by  personal  observation 
as  the  season  advanced  all  possible  information  in  regard  to 
its  habits.  When  the  inspectors  had  gained  sufficient  knowl- 
edge to  enable  them  properly  to  instruct  others,  laborers 
were  employed,  and  each  inspector  was  put  in  charge  of  a 
few  men,  over  whom  he  was  given  full  authority  with  in- 
structions to  recommend  the  discharge  of  any  man  who 
proved  inefficient  or  untrustworthy.  Each  inspector  was 
given  a  short  time  in  which  to  instruct  his  men  by  engaging 
them  in  practical  work  in  the  worst-infested  portions  of 
Maiden  and  Medford.  Then  a  section  (indicated  by  a  map) 
was  allotted  him,  with  instructions  to  inspect  it  and  destroy 
the  eggs  therein.  When  eggs  were  found  on  a  tree  or  other 
object,  certain  characters  were  marked  upon  it  with  white 
paint,  and  the  locality  was  designated  on  the  map. 

As  the  season  advanced  and  the  extent  of  the  region  occu- 
pied by  the  moth  became  known,  it  was  found  necessary  to 
employ  two  hundred  and  fifty  men,  and  distribute  them  over 
this  region.  It  became  evident  that  it  was  impossible  for 
one  man  to  keep  the  entire  field  under  supervision.  Six 
superintendents  were  then  selected  from  among  the  most 
efficient  of  the  inspectors.  Each  of  these  was  required  to 
supervise  the  work  in  several  towns.  When  spraying  began, 
one  man  was  placed  in  charge  of  tools  and  supplies,  including 
spraying  apparatus  and  teams.  A  code  of  rules  and  regula- 
tions was  prepared  and  printed  early  in  the  season,  and  copies 
were  distributed  among  the  employees.  (See  Appendix  B.) 

Daily  Reports  and  Records. 

Each  inspector  was  instructed  to  make  out  daily  a  written 
report  of  the  work  done  by  himself  and  men,  and  to  incor- 
porate in  these  reports  his  observations  on  the  habits  of  the 
moth  and  its  parasites,  notes  on  its  distribution  and  all 
useful  information  acquired  by  him  in  regard  to  the  moth  or 
methods  of  eradicating  it.  In  these  reports  the  number  of 
trees,  buildings,  fences,  walls,  hedges  and  other  objects 
inspected  daily  was  recorded ;  the  number  of  each  on  which 
the  moth  was  found ;  the  number  of  each  form  of  the  moth 


52  THE   GYPSY  MOTH. 

found  and  destroyed  by  hand  on  each  estate ;  the  number  of 
trees  cut  or  treated  by  banding,  burlapping,  cementing  or 
scraping;  and  the  number  of  acres  of  brush  or  woodland 
burned  over.  Mention  was  also  made  of  any  work  left 
unfinished  for  the  time  being,  or  thought  to  be  necessary 
later.  Whenever  the  moths  were  found  in  a  locality  not 
before  known  to  be  infested,  the  inspector  was  required  to 
sketch  on  the  day's  report  a  map  of  the  locality,  marking  the 
colony  in  a  manner  prescribed  and  in  such  a  way  that  it  could 
be  found  at  once  by  one  not  familiar  with  the  place. 

The  name  of  the  inspector  appears  on  each  of  his  daily 
reports,  together  with  the  names  of  his  men.  The  number 
of  hours  per  day  that  each  man  works  is  also  recorded  on 
the  report.  The  reports  are  filed,  and  by  them  it  is  pos- 
sible to  determine  which  inspector  and  men  are  responsible 
for  any  work  done  at  any  point  on  a  given  day  in  any  year, 
and  to  fix  the  responsibility  should  any  omission  of  duty  or 
any  misdemeanor  occur  on  the  part  of  the  employees.  An 
account  with  each  infested  estate  is  kept  in  the  office  in 
books  known  as  "  section  books." 

The  section  books  in  which  the  records  of  field  work  are 
kept  now  number  seventy-eight,  of  one  hundred  pages  each. 
On  the  first  page  of  each  book  the  bounds  and  a  general  de- 
scription of  the  section  are  given,  and  the  work  done  in  it 
and  the  results  attained  for  the  year  are  recorded  on  the 
succeeding  pages.  There  is  also  a  "  blue  print "  map  marked 
in  such  a  way  as  to  designate  each  infested  locality.  (See 
Appendix  C.)  It  is  possible  by  consulting  these  books  to 
learn  how  much  work  has  been  done  on  each  infested  estate, 
how  many  units  of  each  form  of  the  moth  have  been  killed 
by  hand,  and  whether  the  moth  has  been  eradicated  from 
that  locality  or  not.  There  is  thus  kept  a  complete  record 
of  the  progress  made. 

The  Spring  Inspection. 

An  inspection  of  the  infested  region  was  begun  in  March, 
with  a  view  of  determining  its  extent.  This  inspection  com- 
menced in  Medford  and  Maiden  near  the  centre  of  the  region, 
and  extended  to  the  surrounding  towns  as  the  organization 
of  the  force  was  perfected  and  its  size  increased.  Each 


THE  SPRING  INSPECTION.  53 

inspector  was  first  sent  with  his  squad  to  inspect  a  section  in 
one  of  the  towns  then  known  to  be  infested.  He  was  in- 
structed to  inspect  the  entire  territory  within  the  boundaries 
of  the  section,  and  destroy  all  the  eggs  found  therein. 

It  was  at  once  seen  that  the  moth  was  most  numerous 
along  the  thoroughfares.  A  few  of  the  most  expert  men 
were  sent  into  the  towns  nearest  Maiden  and  Medford  to 
examine  the  roadsides  and  mark  any  colonies  found.  These 
men  speedily  found  the  moth  in  Lexington,  Winchester, 
Wakefield,  Melrose,  Eevere  and  Saugus,  thus  greatly  adding 
to  the  knowledge  of  the  extent  of  the  infested  region.  Work 
was  hurried  forward  in  all  these  towns.  The  eggs  were  cut 
or  scraped  from  the  trees  with  knives,  gathered  into  cans 
and  burned  with  oil  in  small  stoves  made  for  the  purpose. 
Rubbish  and  undergrowth  containing  eggs  were  also  de- 
stroyed by  fire.  As  much  more  territory  was  fourfd  infested 
than  was  at  first  estimated,  it  was  found  impossible  to  secure 
and  train  men  enough  to  make  a  thorough  search  of  the  entire 
region  and  destroy  all  the  eggs  before  hatching  time.  As  it 
was  necessary  to  determine  as  soon  as  possible  how  far  the 
moth  had  become  disseminated,  a  portion  of  the  work  in 
Maiden  and  Medford  was  given  up,  and  the  men  who  had 
been  engaged  in  destroying  eggs  there  were  sent  into  the 
outlying  towns.  For  this  reason,  when  the  eggs  began 
hatching  a  considerable  area  yet  remained  in  a  few  of  the 
inner  towns  where  the  eggs  had  not  been  destroyed.  Many 
eggs  which  had  been  scattered  about,  both  by  the  work  of 
the  first  commission  in  the  fall  of  1890  and  by  the  work  in 
the  spring  of  1891,  hatched,  and  caterpillars  began  to  appear 
in  large  numbers  over  a  wide  area.  When  work  was  begun 
the  time  remaining  for  this  inspection  and  egg  killing  did 
not  exceed  six  weeks,  as  the  eggs  begin  hatching  before 
May  1.  Yet  in  that  short  time  the  moths  had  been  found 
far  beyond  the  utmost  limits  of  the  region  previously  known 
as  infested. 

The   Condition  in  which  the  Infested  Region  was  found  in 

1891. 

When  work  was  begun  by  the  second  commission  the  eggs 
of  the  moth  were  found  in  great  numbers  upon  the  trees  in 


54  THE   GYPSY  MOTH. 

certain  localities  in  which  little  work  had  been  done  in  the 
fall  of  1890  by  the  first  commission.  In  some  of  these 
places  the  bark  of  the  trees  was  so  covered  with  egg  clusters 
that  it  presented  a  yellowish  appearance.  This  was  the  case 
only  in  parts  of  Medford  and  at  a  few  points  in  Maiden. 
Wherever  the  first  commission  had  worked  the  previous 
autumn,  few  egg  clusters  were  found  on  the  trees.  It  was 
decided,  however,  to  make  a  thorough  search  of  all  localities 
wherever  it  was  practicable.  With  this  in  view,  the  base 
boards  of  fences  were  taken  off,  plank  walks  raised,  the 
steps  of  houses  torn  up  and  cellars  and  buildings  entered. 
In  such  places  the  eggs  of  the  moth  were  found  concealed 
in  great  numbers.  In  some  cases  quarts  of  eggs  were  taken 
out  from  beneath  piazzas  or  flights  of  steps.  Many  eggs 
were  also  found  in  some  cellars.  As  the  inspection  pro- 
gressed, &  few  badly  infested  localities  were  found  in  other 
towns  and  many  eggs  were  destroyed.  In  most  of  these 
towns  the  moths  had  not  been  colonized  long  enough  to 
become  numerous,  but  were  found  in  isolated  colonies  along 
the  roads.  Such  inspections  as  were  made  of  woodlands 
revealed  in  most  cases  comparatively  few  colonies,  most  of 
them  small  and  isolated. 

A  careful  estimate  has  been  made  from  the  daily  reports  of 
inspectors,  which  shows  the  number  of  egg  clusters  destroyed 
during  the  first  six  weeks  of  1891  to  be  757,760.  The  num- 
ber of  eggs  contained  in  these  clusters  would  probably  be 
from  three  to  five  hundred  millions. 

The  Enforcement  of  Police  Regulations. 
When  in  May  the  caterpillars  were  seen  to  be  dropping 
by  their  threads  from  the  trees  upon  passing  teams  and 
vehicles,  it  was  deemed  necessary  to  do  something  to  check 
their  distribution  in  this  manner.  The  method  (used  by  the 
commission  of  1890)  of  guarding  the  roads  leading  out  of  the 
worst-infested  district  was  tried.  The  police  were  required 
to  inspect  all  horses  and  vehicles  going  out  of  the  infested 
district,  record  all  facts  regarding  their  destination,  and 
destroy  any  caterpillars  found  upon  them.  They  were  also 
required  to  enforce  the  regulations  of  the  department  in 
regard  to  the  hauling  of  hay  or  manure  without  covers,  and 


SPKAYING.  55 

other  matters  relating  to  team  traffic.  The  police  outposts 
were  inspected  by  Professor  Shaler  of  the  committee  in 
charge  of  the  work,  by  the  director  and  by  the  superintend- 
ents, and  it  was  soon  seen  that  the  method  was  impracti- 
cable. A  perfect  cordon  could  not  be  maintained,  and  the 
results  obtained  were  not  proportionate  to  the  expense 
incurred.  At  the  end  of  two  weeks  the  plan  was  abandoned. 
In  the  mean  time  some  good  had  been  done  by  destroying 
caterpillars  found  on  vehicles,  and  by  gaining  a  knowledge 
of  the  destination  of  the  teaming  between  badly  infested 
localities  and  towns  outside  of  the  known  infested  district. 
This  knowledge  was  utilized  in  the  fall  inspection. 

Spraying. 

In  April  the  director's  office  was  removed  to  Maiden,  at  a 
point  near  the  centre  of  the  infested  region  and  having  better 
railway  communications  with  the  surrounding  towns.  More 
commodious  rooms  were  here  secured,  and  experimenting 
with  insecticides  was  begun.  Most  economic  entomologists 
concurred  in  recommending  spraying  with  arsenical  poisons 
for  killing  all  leaf-eating  larvae.  Following  such  advice,  ex- 
periments with  arsenites  were  begun.  An  early  supply  of 
gypsy-moth  larvae  was  obtained  by  artificial  hatching,  and 
the  experimental  work  was  continued  during  the  spring  and 
summer,  the  experiments  with  Paris  green  giving  the  best 
results.  In  the  laboratory  it  was  found  that  young  cater- 
pillars, fed  upon  plants  to  which  this  poison  had  been 
properly  applied,  died  within  a  few  days.  In  later  experi- 
ments it  was  noticed  that  a  considerable  proportion  of  the 
larger  caterpillars  survived.  In  the  experimental  work  in 
the  laboratory,  no  injury  to  the  foliage  was  observed  when  a 
mixture  of  one  pound  of  this  poison  to  one  hundred  and  fifty 
gallons  of  water  was  used.  Glucose  was  also  added  to 
retain  the  poison  upon  the  leaves. 

When  it  became  evident  that  Paris  green  was  the  most 
effective  of  the  arsenites,  preparations  were  made  for  its  use 
on  an  extensive  scale.  In  the  first  part  of  May  teamsters 
were  employed,  and  twenty  spraying  outfits  were  put  upon 
the  road  in  Medford.  The  number  of  men  and  teams  was 
soon  found  to  be  insufficient.  Ten  additional  spraying  out- 


56  THE   GYPSY  MOTH. 

fits  were  purchased,  and  the  capacity  of  each  was  doubled 
by  improved  appliances.  Each  outfit  with  the  accompanying 
squad  of  men  was  under  the  immediate  charge  of  an  inspect- 
or. When  the  apparatus  had  been  tested  and  the  men  had 
gained  the  skill  necessary  for  its  intelligent  use,  the  entire 
force 'was  sent  to  the  periphery  of  the  region  then  known  to 
be  occupied  by  the  moth  and  ordered  to  work  toward  the 
centre.  The  infested  area  was  thus  sprayed  until  the  middle 
of  July.  At  that  date  numbers  of  caterpillars  were  fully 
grown  and  had  stopped  feeding;  some  had  pupated  and 
others  were  wandering  from  tree  to  tree.  Other  means 
were  then  used  for  the  destruction  of  both  caterpillars  and 
pupae. 

Considerable  opposition  to  the  use  of  Paris  green  for 
spraying  was  manifested  by  many  people  living  in  the  in- 
fested towns.  A  mass  meeting  of  opponents  of  the  spraying 
was  held  in  Medford.  One  citizen,  who  attempted  to  cut 
the  hose  attached  to  one  of  the  spraying  tanks,  and  threat- 
ened with  violence  the  employees  of  the  Board  who  had 
entered  upon  his  land,  was  arrested  and  fined.  Others  neu- 
tralized the  effects  of  the  spraying  by  turning  the  garden 
hose  upon  trees  and  shrubs  that  had  been  sprayed,  and 
washing  off  the  solution.  The  opposition  to  the  spraying 
affected  the  results  of  the  work  unfavorably  to  a  consider- 
able extent.  In  June  a  bulletin  of  information  was  issued 
by  the  State  Board  of  Agriculture,  containing  quotations 
from  Professor  Riley  and  other  economic  entomologists  as  to 
the  lack  of  danger  to  man  or  beast  attending  the  use  of  Paris 
green.  This  bulletin  was  distributed  freely  among  the  people 
of  the  district,  but  it  failed  to  allay  the  popular  prejudice 
against  the  spraying. 

During  the  spraying  season  Professor  Riley  and  Mr.  Sam- 
uel Henshaw  (at  that  time  an  entomological  agent  of  the 
United  States  Department  of  Agriculture)  visited  the  dis- 
trict and  inspected  and  criticised  the  operations  in  the  field. 

It  became  evident  before  the  close  of  the  season  that  the 
spraying,  while  reducing  the  numbers  of  the  moth,  could 
not  be  relied  upon  as  a  means  of  extermination,  for  many 
caterpillars  survived  its  effects.  In  June,  when  the  cater- 
pillars had  reached  the  fourth  molt  and  begun  to  cluster  in 


PLATE  X.      Trees  stripped  by  caterpillars  of  the  gypsy  moth,  Arlingtoi 
Mass.    From  a  photograph  taken  July  9,  1891. 


THE   SUMMER  WORK.  57 

cavities  of  the  tree  trunks  and  in  other  hiding  places,  they 
were  destroyed  by  spraying  with  insecticides  which  killed 
them  by  contact.  The  arsenites  have  no  effect  when  used 
in  this  way.  Burlap  bands  were  also  placed  about  the  trees 
to  serve  as  artificial  hiding  places  for  the  caterpillars,  and 
many  were  destroyed  beneath  the  bands.  This  method  was 
so  successful  that  it  was  generally  adopted,  and  more  than 
sixty-eight  thousand  trees  were  banded  during  the  season. 

Entomological  Work. 

On  June  18  Prof.  Charles  H.  Fernald  was  appointed  en- 
tomological adviser  to  the  committee.  Arrangements  were 
made  by  which  he  could  give  a  portion  of  his  time  to  the 
work,  and  one  of  his  assistants,  Mr.  E.  P.  Felt,  was  em- 
ployed in  making  observations  and  experiments.  Professor 
Fernald  critically  examined  the  field  work,  reported  thereon, 
and  made  frequent  subsequent  visits  of  inspection  to  the  in- 
fested territory,  directing  the  experiments  and  giving  advice 
concerning  the  work  in  the  field.  At  his  suggestion  the  in- 
spectors were  directed  to  watch  for  parasites  of  the  moth  in 
its  various  stages.  Several  parasites  were  discovered.  All 
dead  pupre  found  during  the  season  in  the  central  towns  were 
collected  and  preserved,  in  order  that  the  parasites  preying 
upon  them  might  be  obtained.  The  dead  pupae  found  in  the 
outer  towns  of  the  infested  territory  were  left  on  the  trees, 
that  the  parasites  might  escape  from  them  and  continue  their 
work.  The  inspectors  were  encouraged  in  their  observations 
on  the  habits  and  life  history  of  the  moth.  The  feeding 
habits  were  made  the  subject  of  especially  careful  observa- 
tion, and  all  the  information  thus  gained  was  recorded  and 
tabulated  for  future  use. 

Numbers  and  Destructiveness  of  the  Moth  in  the  Summer  of 
1891. 

Though  a  great  number  of  eggs  had  been  burned  in  the 
spring,  and  thousands  of  caterpillars  had  been  killed  by 
spraying,  burning,  burlapping  and  other  means,  they  were 
still  so  numerous  in  the  summer  of  1891  that  some  dam- 
age was  done  in  certain  localities.  A  few  trees  in  some 
orchards  in  Maiden  and  Medford  were  almost  defoliated. 


58  THE   GYPSY  MOTH. 

In  one  case  in  Medford  three  apple  trees  which  had  been 
sprayed  were  only  saved  from  defoliation  by  the  use  of  con- 
tact insecticides.  Two  bushels  of  dead  larvae  and  pupae 
were  gathered  from  the  ground  beneath  these  trees.  The 
injury  was  most  severe  wherever  a  locality  had  been  over- 
looked in  the  spring  inspection,  and  numerous  eggs  thereby 
allowed  to  hatch.  Early  in  June  a  colony  of  moths  was  found 
in  a  small  grove  of  trees  in  Arlington.  Although  the  trees 
were  sprayed  twice  with  a  mixture  of  Paris  green  and  water 
(two  pounds  to  one  hundred  and  fifty  gallons),  the  foliage 
was  entirely  destroyed,  and  the  caterpillars  then  spread  in  all 
directions  through  the  fields,  eating  the  grass  as  they  went. 
In  spite  of  all  that  was  done  to  stay  them,  many  reached  the 
woodland  one-eighth  of  a  mile  away.  Others,  having  de- 
foliated the  trees,  clustered  in  masses  on  the  trunks  and 
branches  and  about  and  upon  the  rocks  beneath.  These 
were  finally  destroyed  by  fire.  After  the  larvae  upon  the 
trees  and  undergrowth  had  been  destroyed,  the  stones 
beneath  the  trees  were  overhauled  and  pupae  were  gathered 
at  the  rate  of  about  eleven  hundred  per  hour  per  man. 
There  were  similar  but  less  destructive  outbreaks  in  other 
parts  of  Arlington,  and  in  Winchester,  Chelsea  and  Melrose, 
but  the  one  of  greatest  magnitude  occurred  in  Swampscott. 
This  was  beyond  the  range  of  the  spring  inspection,  and  the 
colony  was  found  in  July  by  an  inspector  who  had  been  sent 
out  to  search  that  region  for  caterpillars.  It  was  situated  on 
a  hillside  near  Humphrey  Street.  There  were  several  trees 
infested  in  a  yard  and  others  in  a  small  orchard  on  a  hillside 
in  the  rear.  Back  of  the  orchard  was  a  pasture  somewhat 
overgrown  with  trees  and  shrubs.  On  the  east  and  extend- 
ing over  the  highest  point  of  the  hill  there  was  woodland 
composed  of  a  great  variety  of  trees,  both  deciduous  and 
coniferous.  Beginning  at  the  edge  of  the  orchard  a  dense 
undergrowth  or  jungle  of  creeping  vines  and  bushes  extended 
into  the  woodland. 

When  this  colony  was  first  found  the  caterpillars  had  be- 
gun eating  the  foliage  of  nearly  all  species  of  trees  and 
plants  in  the  immediate  vicinity  of  the  house  and  outbuild- 
ings, and  were  fast  spreading  into  the  woodland  and  pasture. 
A  gang  of  men  was  sent  to  the  spot  with  a  spraying  tank 


RAVAGES   OF   1891.  59 

which  was  set  on  a  hill  near  by.  Water  was  drawn  by  a 
hose  from  a  near  hydrant,  and  the  trees,  shrubbery  and  vege- 
tation in  the  whole  neighborhood  were  sprayed  heavily  with 
Paris  green.  As  this  did  not  appear  to  check  the  ravages 
of  the  larvae,  the  locality  was  resprayed  at  once.  Within  a 
few  days  of  the  time  of  the  last  spraying  nearly  every  green 
leaf  on  several  acres  was  eaten  by  the  caterpillars.  This 
destruction  continued  incessantly,  and  the  injury  spread  in 
all  directions.  Six  gangs  of  men  were  despatched  at  once 
with  orders  to  surround  the  infested  locality  and  work 
from  the  outside  to  the  centre,  and  burn  with  an  oil  spray 
all  undergrowth  and  everything  on  which  the  larvae  could 
feed,  destroying  at  the  same  time  with  the  fire  all  the  cater- 
pillars possible.  This  treatment  effectually  checked  their 
diffusion,  thereby  preventing  further  injury.  The  pupae 
were  raked  off  the  worst-infested  trunks  and  burned  or  other- 
wise destroyed. 

Mr.  C.  R.  Drew  of  Medford,  writing  of  the  numbers  of 
the  moth  in  1891  at  his  place,  says  :  — 

There  seemed  to  be  almost  millions  of  gypsy-moth  caterpillars 
in  1891  at  the  corner  of  Fountain  and  Salem  streets,  where  I  then 
lived.  They  very  nearly  destroyed  a  blue  pearmain  apple  tree. 
It  bore  no  fruit  that  year.  This  tree  blossomed  out  in  the  spring, 
but  when  it  began  to  leaf  out  the  caterpillars  attacked  it  and  every 
vestige  of  green  disappeared.  It  looked  as  if  fire  had  run  through 
the  tree.  Several  sweet-apple  trees  were  also  badly  eaten.  You 
could  hear  the  noise  of  the  caterpillars  eating  in  the  trees  at  dusk. 
They  were  so  thick  that  you  could  scrape  them  off  anywhere.  They 
crawled  all  over  the  concrete,  and  we  crushed  them  as  we  walked. 
"We  had  seats  on  the  grass  under  the  trees,  but  we  could  not  sit 
there  because  the  caterpillars  dropped  down  so  thickly.  It  was 
possible  daily  to  gather  a  half  water- bucketful  of  them,  but  the 
next  day  they  would  be  just  as  bad. 

Mr.  L.  B.  Sanderson,  an  employee  of  the  Board,  re- 
ports :  — 

At  Mr.  Drew's  yard  we  got  one  day  twenty-two  quarts  of  cater- 
pillars. 

Such  cases,  however,  were  exceptional,  for  the  greater 
portion  of  moths  in  the  worst-infested  places  were  destroyed 


60  THE   GYPSY  MOTH. 

by  the  agents  of  the  Board  of  Agriculture  before  serious 
injury  had  been  done. 

Fall  Inspection  and  Egg  Gathering. 

In  September,  when  the  moths  had  laid  their  eggs,  the 
force  of  men  was  reduced.  The  most  expert  employees 
were  retained,  and  these  were  engaged  in  destroying  eggs 
in  the  worst-infested  districts  of  Maiden  and  Medford,  until, 
by  practice,  they  had  become  efficient  in  this  sort  of  work. 
As  soon  as  the  leaves  had  fallen  from  deciduous  trees,  the 
men  were  sent  into  the  towns  and  cities  beyond  the  region 
which  the  moth  was  known  to  occupy,  and  the  inspection, 
which  had  been  interrupted  in  the  spring  by  the  growing 
leaves,  was  continued.  An  inspector  was  assigned  to  each 
town,  and  instructed  to  inspect  that  town  hastily,  and  if 
moths  were  found  there  to  proceed  immediately  to  the  next, 
and  so  on  until  a  wide  belt  of  territory  around  the  infested 
region  had  been  inspected  in  which  no  moths  could  be  found. 
Eighteen  towns  and  three  cities  outside  of  the  known  infested 
region  were  thus  inspected  in  November  and  December. 
The  moths  were  found  in  each  of  the  cities  and  in'four  of  the 
towns,  and  it  was  reported  to  the  Legislature  that  whereas 
in  the  spring  the  moths  had  been  supposed  to  be  confined  to 
a  few  towns,  they  were  now  known  to  be  in  thirty  townships, 
as  follows :  Arlington,  Belmont,  Beverly,  Brighton  (Ward 
25,  Boston),  Cambridge,  Charlestown  (Wards  3,  4  and  5, 
Boston),  Chelsea,  East  Boston  (Wards  1  and  2,  Boston), 
Everett,  Lexington,  Lynn,  Lynnfield,  Maiden,  Marblehead, 
Medford,  Melrose,  Peabody,  Eeading,  Revere,  Salem, 
Swampscott,  Saugus,  Somerville,  Stoneham,  Waltham, 
Wakefield,  Watertown,  Winchester,  Winthrop  and  Woburn. 

Remits  of  the    Work. 

During  the  season  of  1891  the  work  carried  on  was  effective, 
inasmuch  as  it  destroyed  all  the  large  colonies  of  the  moth, 
and  protected  the  fruit  and  shade  trees  of  the  State  from 
further  injury.  The  spraying  and  othe'r  treatment  of  the 
trees  redoubled  the  fruit  crop  of  the  district.  The  measures 
used  disposed  of  the  annual  increase  of  the  moth,  and  reduced 
the  numbers  originally  found  by  about  ninety  per  cent. 


RESULTS  OF  THE  WORK  OF   1891.  61 

The  inspection  of  1891  gave  a  closely  approximate  idea  of 
the  size  of  the  region  infested  by  the  moth,  as  it  has  not 
since  been  found  in  any  numbers  or  to  any  distance  outside 
of  the  boundaries  then  laid  down.  As  the  work  was  neces- 
sarily hurried  in  order  to  complete  it  by  Jan.  1,  1892,  so 
that  the  size  of  the  infested  region  might  be  reported  to  the 
Legislature,  many  small  colonies  were  overlooked.  Thus, 
though  the  approximate  area  of  the  infested  region  was 
determined,  its  condition  was  not  thoroughly  known  at  the 
close  of  1891.  It  was  seen  early  in  the  season  that  the 
appropriation  made  would  not  be  sufficient  to  exterminate 
the  moth  in  one  year,  but  it  was  thought  that  $75,000  was 
all  that  could  be  used  to  advantage  until  such  time  as  the 
exact  area  and  condition  of  the  infested  region  could  be 
ascertained. 


THE  GYPSY  MOTH. 


THE  WOKE  OF  1892. 

On  the  first  of  January,  1892,  there  remained  of  the 
appropriation  of  1891  the  sum  of  $5,213.13.  This  could 
have  been  used  to  good  advantage  before  January  1,  but  it 
was  thought  to  be  of  more  importance  to  retain  it,  so  that 
the  most  expert  men  might  be  kept  at  work  until  such  time 
as  another  appropriation  would  become  available.  The 
nucleus  of  an  organization  was  thus  maintained  during  the 
winter.  Early  in  January,  1892,  when  the  Legislature  con- 
vened, the  State  Board  of  Agriculture  by  its  secretary  made 
a  report  recommending  an  appropriation  of  $75,000  for  the 
year.  Though  the  money  available  in  1891  had  proved  in- 
sufficient to  maintain  as  large  a  force  as  was  needed  to  obtain 
the  best  results,  the  committee  deemed  it  unwise  to  recom- 
mend more  than  $75,000  for  the  work  of  1892.  The 
experience  of  1891  had  determined  that  spraying  with 
arsenical  insecticides  (the  method  which  had  been  most 
strongly  recommended  by  the  best  authorities)  was  a  failure 
as  a  means  of  extermination.  The  experimental  work  of  the 
first  year  had  not  resulted  in  providing  a  better  insecticide, 
and  further  experiments  were  necessary.  Again,  much 
difficulty  had  been  experienced  in  securing  efficient  and 
trustworthy  men.  It  was  evident  that  a  large  portion  of 
another  season  must  be  occupied  in  selecting  and  training  a 
body  of  men  which  could  be  used  in  organizing  a  larger  force. 

Although  the  moths  had  been  found  scattered  over  a  region 
of  two  hundred  square  miles,  there  was  considerable  doubt  as 
to  whether  the  extent  of  the  infested  area  had  yet  been 
determined.  Though  the  outlook  was  not  altogether  en- 
couraging, nine-tenths  of  the  moths  in  the  region  found 
infested  had  been  destroyed,  and  there  was  no  immediate 
danger  from  them  so  long  as  they  were  kept  under  control. 
The  committee  were  confident  that  the  moths  could  be  con- 
trolled and  their  numbers  at  the  same  time  still  further 
reduced  with  the  amount  of  money  recommended,  while  in 
the  mean  time  experimental  work  could  be  carried  on  to 
determine  the  policy  for  the  future. 


THE  WORK  OF   1892.  63 

Only  forty  of  the  most  efficient  men  had  been  retained 
from  the  field  force  of  1891,  and  by  reason  of  delay  in 
granting  the  appropriation,  the  committee  were  obliged  to 
discharge  them  all.  Some  of  the  most  capable  of  these  men 
soon  obtained  employment  elsewhere,  and  this  loss  reduced 
the  efficiency  of  the  working  force.  Very  little  work  was 
accomplished  during  the  month  of  February.  Finally,  on 
March  1,  an  act  authorizing  an  appropriation  of  $75,000  was 
passed  by  the  Legislature.  This  made  it  possible  to  make 
arrangements  to  resume  field  work,  although  unseasonable 
snow-storms  still  further  delayed  the  spring  inspection.  The 
old  method  of  scraping  the  eggs  from  the  trees  and  burning 
them  was  discarded,  and  the  eggs  were  left  on  the  trees  and 
treated  with  acids  or  creosote.  The  scattering  of  eggs  was 
thus  avoided. 

The  experimental  work  of  1891  resulted  in  the  trial  in  the 
field  in  1892  of  several  new  insecticides.  None  of  them, 
however,  proved  generally  effective,  although  bromine  and 
chlorine  were  useful  in  destroying  eggs  in  hollow  trees. 

Professor  Fernald  had  recommended  in  December,  1891, 
' '  that  the  nests  of  the  gypsy  moth  hereafter  gathered  be  pre- 
served in  such  a  way  that  the  eggs  of  parasites  that  may  have 
been  laid  in  such  eggs  of  the  gypsy  moth  be  allowed  an 
opportunity  to  develop  into  the  perfect  insect."  This  plan 
was  put  into  operation  early  in  1892  in  the  towns  of  Maiden 
and  Medford.  All  the  eggs  gathered  were  taken  to  a  central 
point  in  each  town,  and  were  there  kept  in  a  closed  case  until 
all  were  hatched.  As  only  a  single  specimen  of  an  egg 
parasite  was  obtained  in  this  way,  the  plan  was  aban- 
doned. 

Owing  to  the  lateness  of  the  appropriation,  which  caused 
delay  in  examining  and  employing  men,  and  the  unseason- 
able weather,  it  was  impossible  before  hatching  time  to  make 
a  thorough  inspection  of  the  infested  region,  but  an  attempt 
was  made  to  destroy  all  egg  clusters  found  along  the  roads. 
This  was  done  to  prevent  the  spreading  of  the  caterpillars. 
This  method  was  intended  to  take  the  place  of  police  out- 
posts on  the  roads.  It  was  a  preventive  measure,  for,  if  the 
eggs  were  removed  from  the  trees,  there  would  be  no  cater- 
pillars to  spin  or  drop  down  upon  the  passing  vehicles  and 


64  THE   GYPSY  MOTH. 

teams.  It  was  in  this  manner  that  the  moths  had  been  dis- 
tributed in  former  years.  Wherever  large  trees  near  high- 
ways had  been  cleared  of  eggs,  they  were  banded  with  tree  ink 
or  with  "Raupenleim"  ("insect  lime")  to  prevent  the  cater- 
pillars ascending  them  from  the  ground.  This  was  intended 
to  keep  the  moth  out  of  such  trees  for  the  season.  Very 
little  spraying  was  done  during  1892.  Two  spraying  outfits 
were  kept  busy  for  a  short  time,  and  were  sent  from  place  to 
place  wherever  the  caterpillars  appeared  in  considerable  num- 
bers. The  trees  in  such  localities  were  sprayed  when  the 
caterpillars  were  small,  and  many  of  the  latter  were  killed. 
This  served  to  lessen  the  dissemination.  The  method  of 
burlapping  trees  was  used  in  place  of  spraying,  and  was  ex- 
tensively employed  over  most  of  the  infested  region.  The 
force  of  employees,  numbering  two  hundred  and  thirty-four 
during  the  spring  inspection,  was  afterwards  reduced,  but  was 
again  increased  during  the  inspection  of  burlaps.  The  ap- 
propriation was  not  sufficient,  however,  to  provide  enough 
men  to  thoroughly  examine  the  burlaps.  Notwithstanding 
this  disadvantage,  burlapping  and  hand- killing  during  the 
summer  disposed  of  nine-tenths  of  the  gypsy  moths  in  the 
places  known  to  be  infested,  and  in  many  localities  they 
were  exterminated  by  this  work  alone. 

During  the  fall  inspection  an  attempt  was  made  to  search 
the  country  thoroughly,  but  again  the  lack  of  money  was 
felt,  and  it  was  found  necessary  soon  after  the  first  of  Sep- 
tember to  discharge  a  large  proportion  of  the  force.  Only 
about  forty  of  the  most  expert  men  could  be  retained.  It 
was  impossible  with  this  number  of  men  to  make  a  thorough 
examination  of  the  entire  infested  region.  A  great  deal  of 
effort  was  devoted  to  determining  whether  the  moth  had 
spread  farther  than  had  been  reported  in  1891.  A  consider- 
able proportion  of  the  later  expenditure  of  the  year  was  thus 
used  in  the  towns  immediately  surrounding  the  infested 
region.  But  the  moth  was  not  discovered  in  any  other 
towns  in  1892. 

The  infested  region  was  so  well  covered  by  the  distribu- 
tion of  the  force  that  no  serious  outbreak  of  the  moth 
occurred  in  1892.  Enough  had  now  been  learned  of  the 
condition  of  the  infested  territory  to  convince  the  committee 


LARGER  APPROPRIATIONS  NEEDED.    65 

that  larger  appropriations  were  needed.  They  believed  that 
they  had  now  learned  by  experience  how  to  eradicate  the 
moth.  A  large  number  of  colonies  had  already  been  exter- 
minated, and  it  had  been  proved  that  the  moths  could  be  ex- 
terminated wherever  they  were  found.  The  committee  in  its 
annual  report  to  the  Board  recommended  that  an  appropri- 
ation of  $165,000  be  granted  for  the  work  of  1893.  The 
report  was  accepted  by  the  Board,  and  presented  to  the 
Legislature  of  1893.  The  report  begins  as  follows  :  — 

In  presenting  the  report  of  the  gypsy  moth  department  of  the 
State  Board  of  Agriculture,  in  accordance  with  the  provisions  of 
chapter  210,  Acts  of  1891,  the  committee  desires  to  call  attention 
to  the  fact  that  this  effort  to  exterminate  the  Ocneria  dispar  is  the 
first  attempt  on  a  large  scale  ever  made  in  this  Commonwealth  to 
destroy  a  species  of  insect,  consequently  there  was  no  trustworthy 
experience  to  guide  the  work.  As  it  was  an  imported  insect,  its 
habits  and  peculiarities  in  this  country  had  to  be  ascertained 
before  the  most  effective  methods  of  destruction  could  be  deter- 
mined. 

Much  of  the  work  that  has  been  done  may  be  considered  as  in 
a  measure  experimental.  As  we  have  become  more  familiar  with 
the  extent  of  the  territory  invaded  by  the  moth,  the  magnitude  of 
the  task  has  become  more  apparent.  When  the  Legislature  made 
the  first  appropriation,  it  was  supposed  that  the  moth  occupied 
but  a  small  part  of  one  town.  Careful  inquiry  has  shown  that  it 
infests  thirty  cities  and  towns.  From  our  observations  we  have 
no  doubt  that  it  was  in  nearly  everyone  of  these  localities  in  1890, 
when  the  campaign  of  extermination  was  commenced.* 

During  the  year  much  had  been  done  toward  inspecting 
the  towns  on  the  borders  of  the  infested  district.  Of  this, 
the  committee  reports  :  — 

Much  effort,  involving  a  large  expenditure,  has  been  devoted  to 
the  inspection  of  territory  outside  the  infested  limit.  Numerous 
letters  have  been  received  from  different  parts  of  the  State  and 
from  adjoining  States,  to  the  effect  that  supposed  gypsy  moths 
had  been  found.  These  notices  have  in  all  cases  led  to  an  inspec- 
tion of  the  suspected  locality.  The  towns  just  outside  those 

*  Report  of  the  State  Board  of  Agriculture  on  the  Extermination  of  the  Gypsy 
Moth,  January, 


66  THE   GYPSY  MOTH. 

infested  have  also  received  some  attention,  but  in  no  case  has  the 
gypsy  moth  been  found  outside  of  the  limits  reported  last  year.* 

Such  expert  men  as  could  be  spared  from  other  work  had 
been  detailed  to  examine  as  much  as  possible  of  the  large 
wooded  region  in  the  infested  territory,  so  that  its  condition 
might  be  reported  on  as  fully  as  possible  to  the  Legislature. 
The  woodland  was  found  to  be  more  or  less  infested,  but  its 
exact  condition  could  not  be  determined,  owing  to  a  lack  of 
money  and  trained  men.  On  what  was  known  of  its  condi- 
tion, the  committee  based  their  recommendation  for  a  larger 
appropriation,  setting  forth  their  plans  in  regard  to  it  in  the 
following  words :  — 

We  desire  to  present  to  the  Legislature  the  state  of  the  problem 
and  various  plans  for  solving  it,  with  an  estimate  of  the  cost  of 
each  class  of  work  for  the  next  year.  There  are  large  areas  of 
woodland  in  the  infested  towns.  There  are  points  in  these  forested 
districts  known  to  be  infested.  There  are  probably  other  points 
where  colonies  have  been  established,  and  possibly  many  such. 
The  dense  growth  of  the  underbrush  in  this  woodland,  and  the 
thick  carpet  of  dead  leaves  on  the  ground,  make  perfect  inspection 
almost  impossible.  There  are  about  four  hundred  acres  of  this 
woodland,  which  will,  if  it  is  allowed  to  remain,  continue  to  be  an 
uncertain  element  in  our  problem. 

If  the  timber  could  be  felled  and  burned  on  the  ground  during 
the  winter  and  early  spring,  and  the  ground  carefully  burned  over 
twice  during  the  summer,  that  element  would  be  eliminated.  We 
estimate  the  cost  of  this  work  at  $125  per  acre,  or  a  total  of 
$50,000 ;  but  we  are  confronted  with  the  fact  that  most  of  the 
forest  is  situated  in  Medford,  Maiden,  Arlington,  Melrose,  Win- 
chester and  Stoneham,  and  that  much  of  it  is  valued  for  prospective 
parks.  Its  destruction  would  be  considered  a  calamity  by  the  in- 
habitants of  these  places. 

We  believe  that  with  sufficient  means,  and  in  several  years' 
time,  these  forest  lands  can  be  cleared  of  moths  without  destroy- 
ing the  timber.  To  accomplish  it  all  the  underbrush  and  all  the 
decayed  and  worthless  trees  must  be  cut  and  destroyed  by  fire, 
the  ground  burned  over,  and  the  whole  carefully  inspected  at  least 
twice  each  year.  Burlaps  must  be  placed  wherever  the  moth 
appears  or  has  been  found  previous  to  the  clearing  up.  The  latter 

*  Report  of  the  State  Board  of  Agriculture  on  the  Extermination  of  the  Gypsy 
Moth,  January,  1893,  page  6. 


A  LARGER  APPROPRIATION  URGED.         67 

plan  will  in  the  aggregate  cost  more  than  the  former,  but,  as  the 
work  need  not  necessarily  be  all  done  at  once,  and  as  it  could  be 
done  in  connection  with  the  other  work  of  the  department,  utilizing 
the  time  of  the  men  in  the  winter  and  early  spring,  it  may  be  the 
best  plan  to  pursue.* 

The  committee  had  undertaken  to  secure  as  full  informa- 
tion as  possible  in  regard  to  European  experience  with  the 
gypsy  moth  and  the  methods  used  in  Europe  to  combat  it, 
as  well  as  the  probabilities  regarding  its  future  in  this  coun- 
try and  the  destruction  which  would  be  caused  by  it  if  it 
were  allowed  to  spread  unchecked  except  by  individual 
effort.  The  information  thus  gained  was  tersely  embodied 
in  the  report  to  the  Legislature,  as  a  warning  to  show  what 
might  be  expected  in  the  future.  Tables  of  damage  done  to 
crops  in  the  United  States  by  insects  were  presented  in  the 
field  director's  report.  The  entomologist,  who  had  at  first 
grave  doubts  of  the  possibility  of  complete  extermination, 
stated  in  his  report  that  he  had  been  led  to  believe  that  such 
a  thing  was  really  possible,  provided  the  work  were  continued 
for  several  years  with  sufficient  appropriations  to  keep  the 
entire  territory  under  careful  supervision.  The  State  Board 
of  Agriculture,  approving  the  action  of  its  committee,  urged 
that  the  appropriation  recommended  be  granted,  and  that 
every  effort  be  made  at  once  to  rid  the  State  of  the  pest. 


*  Report  of  the  State  Board  of  Agiiculiure  on  the  Extermination  of  the  Gypsy 
Moth,  January,  1893,  page  7. 


68  THE   GYPSY  MOTH. 


THE    WORK    or    1893. 

Pursuant  to  the  recommendation  of  the  State  Board  of 
Agriculture,  the  joint  standing  committee  on  agriculture  of 
the  Legislature  of  1893  reported  a  resolve  appropriating 
$165,000  for  the  extermination  of  the  gypsy  moth.  While 
this  resolve  was  before  the  committee  on  finance,  the  com- 
mittee on  the  extermination  of  the  gypsy  moth  voted  "to 
suggest  to  the  committee  on  finance  that  they  advise  the 
appointment  of  a  committee  of  three  or  five  of  the  Legislat- 
ure to  investigate  the  work  of  the  committee  of  the  Board 
of  Agriculture  during  the  year  1893,  and  make  such  a  report 
to  the  next  Legislature  as  in  their  judgment  seems  wise." 
No  such  committee  was  appointed.  Members  of  the  Board 
of  Agriculture  appeared  before  the  committee  on  finance  to 
advocate  the  appropriation  of  $165,000.  Expert  entomol- 
ogists and  many  citizens  of  the  infested  district  also  appeared 
or  sent  communications,  advising  that  every  possible  effort 
be  made  to  exterminate  the  moth,  and  that  the  Board  of 
Agriculture  be  given  the  full  appropriation.  But  the  finance 
committee  reported  in  favor  of  reducing  the  amount  to 
$100,000. 

There  was  considerable  delay  in  granting  this  appropria- 
tion, and,  as  the  money  remaining  from  1892  was  nearly 
exhausted,  it  became  necessary  to  suspend  all  field  work. 
While  the  work  was  thus  suspended  and  the  committee  was 
awaiting  an  appropriation,  as  in  1892,  several  of  the  most 
experienced  men  obtained  other  situations.  This  loss  reduced 
the  efficiency  of  the  force.  By  reason  of  the  delay  several 
weeks  of  the  best  working  time  of  the  year  passed  unutilized. 
On  April  12  an  appropriation  of  $100,000  was  made  by  the 
Legislature.  A  resolve  was  also  sent  to  Congress  by  the 
Legislature,  asking  for  $100,000  additional  to  continue  the 
work.  This  resolve  got  no  further  than  the  committee  room, 
and  was  never  entertained  by  Congress. 

As  soon  as  the  appropriation  became  available,  field  work 
was  again  commenced.  The  force  of  men  was  increased  as  fast 
as  was  compatible  with  their  proper  examination  and  training. 


VISITS  FEOM  ENTOMOLOGISTS.  69 

The  short  time  remaining  before  egg-hatching  time  was  util- 
ized in  destroying  eggs  in  the  worst- infested  towns,  and 
searching  for  them  in  the  outer  and  less-infested  towns. 
The  trees  in  infested  localities  were  banded  with  burlaps. 
During  the  summer  the  burlaps  in  the  outer  towns  were 
visited  daily,  and  the  trees  were  occasionally  examined, 
both  by  the  regular  men  and  by  special  inspectors.  By 
this  means  the  moth  was  almost  completely  eradicated 
from  such  towns,  and  in  some  of  these  towns  no  eggs  were 
found  during  the  autumn.  Owing  to  the  insufficiency  of  the 
appropriation  and  the  consequent  lack  of  men,  the  burlaps 
in  the  central  towns  were  not  as  often  visited.  As  the  effec- 
tiveness of  this  method  depends  on  daily  visits  to  the  bands, 
the  results  here  were  not  as  satisfactory  as  in  the  outer  towns, 
but  the  moths  were  held  in  check  and  somewhat  reduced  in 
numbers. 

During  the  summer  an  experiment  in  trapping  the  male 
moths  was  tried,  with  a  view  of  determining  whether  the 
number  of  fertile  eggs  would  be  decreased  thereby.  Experi- 
ments with  insecticides  during  the  season  proved  the  useful- 
ness of  a  new  insecticide,  —  arsenate  of  lead.  Raupenleim 
was  used  to  a  considerable  extent  in  1893,  as  it  was  during 
1892,  but  was  not  found  so  effective,  perhaps  by  reason  of 
its  inferior  quality. 

In  May  the  committee  voted  to  request  Professor  Fernald 
to  invite  six  of  the  most  prominent  entomologists  in  the  ad- 
joining States  to  visit  the  infested  region  and  critically 
examine  the  field  and  office  work,  and  report  the  results  of 
their  observations.  Prof.  Clarence  M.  Weed,  D.Sc.,  of  the 
New  Hampshire  State  College,  Dr.  A.  S.  Packard  of  Brown 
University,  Dr.  J.  A.  Lintner,  State  entomologist  of  New 
York,  Professor  John  B.  Smith  of  Rutgers  College,  State 
entomologist  of  New  Jersey,  and  Dr.  H.  T.  Fernald,  profes- 
sor of  zoology  at  the  Pennsylvania  State  College,  visited  the 
territory  in  the  summer,  examined  and  criticised  the  work, 
and  reported  upon  it.  Their  reports  will  be  found  in  Ap- 
pendix D.  The  recommendations  of  these  entomologists 
were  carefully  considered  by  Professor  Fernald  and  the 
director,  who  reported  to  the  committee  that  the  suggestions 
made  should  be  carried  out  as  far  as  practicable. 


70  THE  GYPSY  MOTH. 

With  the  increased  force  provided  by  the  larger  appropria- 
tion, it  was  possible  to  accomplish  in  1893  much  more  than 
had  been  done  in  former  years.  Every  effort  was  made  to 
determine  how  far  the  moth  had  spread,  and  whether  it  had 
passed  beyond  the  limits  of  the  region  known  to  be  infested 
in  1891.  Careful  inspection  was  made  of  a  large  number  of 
towns  on  the  border  line  of  the  infested  region,  which  resulted 
in  small  colonies  being  found  in  three  places  just  outside  the 
line  drawn  in  1891.  It  was  evident  that  these  colonies  had 
been  in  existence  for  several  years,  even  before  the  work  of 
extermination  was  begun.  One  other  colony  was  found  at 
Franklin  Park  in  Boston.  This  had  evidently  been  growing 
for  at  least  four  or  five  years.  Efforts  were  made  to  exter- 
minate the  moth  from  the  outer  belt  of  towns  of  the  infested 
region.  These  efforts  were  so  successful  that  at  the  end  of 
the  year  no  form  of  the  moth  was  found  in  any  of  the  follow- 
ing towns:  Beverly,  Brighton,  Burlington,  Charlestown, 
Danvers,  Lynnfield,  Marblehead,  Reading,  Waltham  and 
Watertown. 

During  the  season  more  than  eight  hundred  colonies  of 
the  moth  had  been  exterminated.  But  a  detailed  search  of 
certain  portions  of  the  woodland  in  the  infested  region,  which 
had  been  suspected  but  had  not  been  known  before  to  be 
infested,  revealed  small  colonies  scattered  here  and  there, 
indicating  that  while  a  large  proportion  of  the  force  had 
been  concentrated  upon  the  outer  towns  with  a  view  to 
exterminating  the  moth  there,  the  problem  had  been  increas- 
ing from  within  by  the  spreading  of  the  moths  into  the 
woodlands  in  the  interior  towns. 

The  Board  of  Agriculture  in  its  annual  report  on  the 
gypsy-moth  work  to  the  Legislature  again  advised  that 
everything  possible  be  done  to  exterminate  the  moth,  and 
recommended  that  $165,000  be  appropriated  for  the  work 
of  the  ensuing  year.  The  magnitude  of  the  work  and  the 
possibility  of  destruction  to  the  forests  were  stated,  and 
the  plans  for  dealing  with  the  moth  in  the  woodland  were 
described.  Statements  from  citizens  were  given  showing  the 
destruction  of  trees  and  garden  plants  which  had  been  accom- 
plished by  the  moth  in  Massachusetts  during  the  years  before 
the  State  began  the  work  of  extermination. 


THE  INFESTED  REGION  REDUCED.          71 

It  was  shown  in  the  report  that  the  region  occupied  by 
the  moth  had  been  considerably  reduced  by  the  work  already 
done,  and  the  belief  of  the  committee  was  stated  that  with  the 
appropriation  asked  for  still  more  could  be  accomplished 
toward  reducing  the  infested  area.  The  report  described  the 
probable  condition  of  the  parks,  woodlands  and  farms  of 
the  State  should  the  moth  be  allowed  to  go  on  unchecked. 
Every  effort  was  made  to  place  fully  before  the  Legislat- 
ure the  necessity  of  continuing  the  work  with  a  view  to 
extermination. 


72  THE   GYPSY   MOTH. 


THE    WORK    OF    1894. 

Remembering  the  experience  of  former  years,  and  con- 
sidering the  likelihood  of  similar  delay  on  the  part  of  the 
Legislature  and  a  consequent  embarrassment  of  the  work, 
the  committee  had  laid  their  plans  for  1893  so  as  to  retain 
a  considerable  portion  of  that  year's  appropriation  with  which 
to  begin  the  season  of  1894.  On  Jan.  1,  1894,  $29,744.69 
of  that  appropriation  remained  unexpended.  This  was  re- 
tained in  order  that  the  most  expert  men  of  the  force  of  1893 
could  be  employed  until  such  a  time  as  the  Legislature  should 
make  another  appropriation.  There  were  eighty-three  men 
at  work  on  January  1. 

Early  in  the  year,  Prof.  N.  S.  Shaler,  who  had  been  a  mem- 
ber of  the  committee  from  its  organization  in  1891  and  who  had 
been  most  active  and  prominent  in  the  work,  was  obliged  to 
resign  from  the  Board  of  Agriculture  on  account  of  the  press- 
ure of  other  duties.  Since  his  resignation,  however,  he  has 
kindly  given  his  advice  and  assistance  whenever  called  upon. 

On  January  16,  an  order  was  presented  to  the  Legislature 
by  Representative  Bullock  of  Fall  River,  which  was  after- 
wards adopted.  This  appears  below,  together  with  the 
answer  made  to  it  by  the  Board  of  Agriculture  :  — 

Ordered,  That  the  State  Board  of  Agriculture  be  instructed  to 
report  in  writing  to  the  General  Court,  on  or  before  the  first  day 
of  February  next,  the  following  facts  and  estimates  relative  to  the 
work  of  exterminating  the  gypsy  moth  :  — 

1.  The  amount  appropriated  and  amount  expended  annually 
for  such  purpose  since  the  work  began. 

2.  The  amount  per  year  which,  in  the  estimation  of  said  Board, 
it  will  be  necessary  to  expend  upon  such  work  during  the  next  ten 
years. 

3.  Whether,  in  the  estimation  of  said  Board,  it  will  be  neces- 
sary to  continue  the  work  of  extermination  for  an  indefinite  period. 

4.  If  it  will  not  be  necessary  to  continue  said  work  for  an  in- 
definite period,  what  is  the  probable  limit  of  time  during  which  it 
will   be  necessary   to  continue  said  work,  and   what  will  be  the 
probable  necessary  expenditure  therefor,  in  the  aggregate,  after 
the  expiration  of  ten  years  from  date. 


THE  EXPENSE  OF  THE   WORK.  73 


REPLY  BY  THE  BOARD. 

To  the  Senate  and  House  of  Representatives  of  the  Commonwealth  of 
Massachusetts. 

In  response  to  an  order  of  the  Legislature  under  date  of  Jan. 
15,  1894,  the  State  Board  of  Agriculture,  by  its  gypsy  moth  com- 
mittee, presents  the  following  "  facts  and  estimates  relative  to  the 
work  of  exterminating  the  gypsy  moth."  The  amounts  of  appro- 
priations and  expenditures  have  been  reported  in  the  several 
annual  reports  of  the  committee,  and  a  summary  of  the  same  ap- 
pears in  the  report  of  the  work  of  1893,  now  in  the  hands  of  the 
Legislature.  The  original  bills  and  pay-rolls,  showing  the  details 
of  all  expenditures,  may  be  found  in  the  office  of  the  State  Auditor 
in  the  State  House. 

The  following  is  a  condensed  account  of  the  appropriations  made 
and  the  amounts  expended  annually :  — 

APPROPRIATIONS. 

March  14, 1890, $25,000  00 

June       3, 1890, 25,000  00 

June       3,  1891,      . 50,000  00 

1892, 75,000  00 

1893, 100,000  00 

Total  appropriated, $275,000  00 


EXPENDED  IN  1890  BY  FIRST  COMMISSION. 

Salary  of  commissioners, $3,11827 

Wages  of  employees, 15,27832 

Other  expenses, 7,142  73 


Total  expended  in  1890, $25,539  32 

EXPENDED  IN  1891  sr  SECOND  COMMISSION. 
Balance   of  salaries  due   members  of 

first  commission,         ...         .    $630  95 
Salary  of  director,  one  and   one-half 

months,        .        ....         .       300  00 

Wages  of  employees,     .      •  .        .        .  10,147  97 
Other   expenses,   including   travelling 

expenses,  teaming,  rent,  supplies  and 

tools 2,378  54 

$13,457  46 


Amounts  carried  fonvard,       ....  $13,457  46   $25,539  32 


74 


THE  GYPSY  MOTH. 


Amounts  brought  forward, 


.  $13,457  46   $25,539  32 


EXPENDED  IN  1891  BY  THE  STATE  BOARD  OF 
AGRICULTURE. 

Expenses  of  committee  in  charge  of 
the  work,  ^  .  .  .  .  .  .  $121  53 

Director's  salary,  seven  and  one-half 
months, 1,500  00 

Advising  entomologist's  salary  and  ex- 
penses, .  .  .  .  .  .  280  84 

Wages  of  employees,  ...  41,096  86 

Other  expenses,  including  travelling 
expenses,  teaming,  rent,  supplies  and 
tools, 12,790  86 


55,790  09 


Total  expended  in  1891, 


69,247  55 


EXPENDED  IN  1892  HY  THE  STATE  BOARD  OF  AGRICULTURE. 
Expenses  of  the  committee  in  charge  of  the  work,      $130  49 

Director's  salary, 2,400  00 

Advising  entomologist's  salary  and  expenses,      .        525  60 

Wages  of  employees, 59,505  03 

Other  expenses,  including  travelling  expenses, 
teaming,  rent,  supplies  and  tools,       .         .        .    11,979  84 


74,540  96 


EXPENDED  IN  1893  BY  THE  STATE  BOARD  OF  AGRICULTURE. 

Expenses  of  committee  in  charge  of  the  work,      .  $11028 

Director's  salary, 2,400  00 

Advising  entomologist's  salary  and  expenses,       .  730  16 

Wages  of  employees, 59,039  65 

Other  expenses,  including  travelling  expenses, 

teaming,  rent,  supplies  and  tools,      .        .        .  13,647  39 


75,927  48 


Total  expended  to  Jan.  1,  1894, 


.  $245,255  31 


The  estimates  called  for  must,  from  the  nature  of  the  attending 
circumstances,  be  only  opinions.  The  plans  for  the  work  of  1893, 
for  which  an  appropriation  of  SI 65, 000  was  asked,  contemplated 
a  careful  tree  to  tree  search  of  all  the  forest  land  within  the  in- 
fested territory.  This  search  would  have  cost  a  very  large  sum  ; 
but  as  only  sixty  per  cent,  of  the  sum  asked  was  appropriated, 
this,  with  much  other  work  planned  for  the  central  district,  was 
necessarily  postponed.  It  was  decided  that  the  work  of  extermi- 
nation in  the  outer  infested  towns  and  the  inspection  of  the  terri- 
tory surrounding  them  still  further  out  was  most  necessary  and 
would  contribute  most  toward  extermination.  Were  the  uucer- 


FUTURE  EXPENSE  ESTIMATED.  75 

tainties  which  confront  us  in  the  condition  of  these  forest  lands 
eliminated,  our  opinions  would  more  nearly  approximate  to  the 
character  of  estimates  made  by  experts  when  all  the  conditions  of 
a  problem  are  known. 

In  1893  considerable  progress  toward  extermination  was  made. 
Ten  towns  were  apparently  cleared,  comprising  more  than  one-third 
of  the  territory  originally  infested.  In  1894,  with  the  appropriation 
asked  for  ($165,000),  the  committee  ought  to  be  able  to  bring 
into  the  same  category  Swampscott,  Salem,  Peabody,  Wakefield, 
Woburn,  Lexington,  Winthrop  and  Franklin  Park.  This  would 
leave  Belmont,  Arlington,  Cambridge,  Chelsea,  East  Boston,  Ever- 
ett, Lynn,  Maiden,  Medford,  Melrose,  Eevere,  Saugus,  Somerville, 
Stoneham  and  Winchester  still  infested.  Several  of  these  towns 
should  be  very  nearly  or  quite  cleared  in  1894.  But  we  have,  in 
our  estimates,  left  them  with  the  list  of  probably  uncleared.  If, 
in  1895,  $150,000  is  appropriated,  the  work  of  that  year  should 
clear  all  towns  but  Arlington,  Chelsea,  Everett,  Maiden,  Medford, 
Melrose,  Revere,  Saugus  and  Somerville.  The  moth  in  these 
towns  should  then  be  brought  to  the  verge  of  extermination  so 
that,  with  an  appropriation  of  $100,000,  the  work  of  1896  would 
be  quite  likely  'to  bring  them  very  near  to  the  condition  of  the 
cleared  towns.  During  all  this  time  a  large  amount  of  this  money 
must  be  expended  in  closely  inspecting  the  towns  supposed  to  be 
cleared.  In  1897  an  appropriation  of  $50,000  would  be  necessary 
to  provide  for  the  completion  of  the  work  in  the  last-mentioned 
towns  and  for  the  necessary  careful  reinspection  of  the  whole 
territory.  We  think  this  appropriation  would  also  provide  means 
to  stamp  out  any  possible  remains  of  colonies  supposed  to  be 
exterminated  that  might  be  found  by  the  careful  reinspection. 
For  the  five  succeeding  years  we  believe  that  an  average  annual 
appropriation  of  $25,000  would  be  necessary  to  continue  the  care- 
ful inspection  of  the  whole  territory  and  provide  the  means  to  deal 
with  any  colonies  that  may  possibly  have  been  overlooked.  While 
it  is  our  opinion  that  it  is  quite  possible  to  exterminate  the  moth 
if  large  appropriations,  such  as  have  been  mentioned,  are  granted 
for  the  next  few  years,  we  believe  it  also  probable  that  should  an 
appropriation  of  only  $50,000  per  year  be  granted  the  work  would 
have  to  be  continued  indefinitely,  as  a  very  large  proportion  of 
such  an  appropriation  would  necessarily  be  expended  in  watching 
the  outside  territory  and  taking  measures  to  prevent  the  spreading 
of  the  insect. 

Another  method  of  estimating  the  probable  future  cost  of  exter- 
mination would  be  to  multiply  the  average  cost  of  extermination 
per  estate  in  the  towns  already  cleared  by  the  number  of  estates 


76  THE   GYPSY  MOTH. 

still  infested.  We  estimate  the  number  of  estates  still  infested  at 
eight  thousand.  Our  records  show  that  the  average  cost  of  exter- 
mination, per  estate,  in  the  towns  cleared  has  been  $41.10.  At 
the  same  rate,  the  cost  of  exterminating  the  moth  from  eight 
thousand  estates  would  be  $328,800.  This  statement  is  made  on 
the  assumption  that  the  estates  yet  infested  are  now  in  no  worse 
condition  than  were  those  which  had  been  cleared.  This  computa- 
tion does  not  include  the  large  sum  which  must  necessarily  be 
expended  in  inspecting  territory  already  cleared,  that  outside  which 
must  be  watched,  and  the  cost  of  reinspection  for  several  years  of 
these  eight  thousand  estates  after  extermination  is  believed  to 
have  been  accomplished. 

In  the  opinion  of  the  committee  the  above-mentioned  estimates 
afford  the  closest  approximation  to  a  forecast  that  can  well  be 
made.  It  is  proper,  however,  to  state  that  the  questions  asked 
by  the  Legislature  cannot  be  answered  with  certainty. 

Respectfully  submitted, 
Per  order  of  the  Gypsy  Moth  Committee 

of  the  State  Board  of  Agriculture, 

WM.  R.  SESSIONS,  Chairman. 
JAN.  29,  1894. 

At  the  annual  meeting  of  the  Board  of  Agriculture  on 
February  8,  new  by-laws  were  adopted,  affecting  a  reorgan- 
ization of  the  Board.  The  committee  in  charge  of  the  gypsy- 
moth  work  was  thereafter  known  as  the  "  committee  on  the 
gypsy  moth,  insects  and  birds,"  and  its  number  was  increased 
to  six. 

The  following  is  the  article  under  which  this  committee 
acts : — 


It  shall  be  charged  with  the  duties  of  the  gypsy  moth  committee, 
as  provided  for  in  chapter  210  of  the  Acts  of  1891.  All  matters 
relating  to  birds  and  insects  shall  be  referred  to  this  committee, 
who  shall  report  to  the  Board  from  time  to  time. 

The  following  members  of  the  Board  were  elected  to  serve 
upon  this  committee :  E.  W.  Wood  of  Newton,  Chairman, 
Wm.  R.  Sessions  of  Hampden,  Francis  H.  Appleton  of  Pea- 
body,  Wm.  H.  Bowker  of  Boston,  F.  W.  Sargent  of  Ames- 
bury,  and  Augustus  Pratt  of  North  Middleborough. 


MR.   APPLETON'S   RESIGNATION.  77 

In  the  mean  time  the  recommendation  of  the  Board  for  an 
appropriation  of  $165,000  for  the  work  of  the  year  had  been 
considered  by  the  legislative  committees.  The  joint  stand- 
ing committee  on  agriculture  had  unanimously  endorsed  the 
recommendation  and  had  reported  a  bill  to  the  House  provid- 
ing for  an  appropriation  of  $165,000.  The  committee  on  the 
gypsy  moth,  insects  and  birds,  together  with  many  citizens 
from  the  infested  district,  appeared  before  the  committee  on 
expenditures  and  urged  that  the  full  amount  of  the  appro- 
priation be  granted.  But  the  latter  committee,  disregarding 
the  recommendation  of  the  committee  on  agriculture,  reported 
a  bill  recommending  an  appropriation  of  $100,000.  The 
committee  on  the  gypsy  moth,  insects  and  birds  also  urged 
that  a  committee  of  the  Legislature,  consisting  of  three  or 
five,  be  appointed  to  fully  investigate  the  gypsy-moth  work 
during  the  season  and  report  to  the  next  Legislature.  This 
was  not  done. 

When  it  became  known  later  that  the  Legislature  had  not 
approved  the  recommendation  of  the  committee,  and  that  only 
$100,000  had  been  appropriated,  Mr.  Francis  H.  Appleton, 
one  of  the  original  members  of  the  committee,  tendered  to 
the  Board  of  Agriculture  his  resignation  as  a  member  of  the 
committee.  The  reasons  given  by  Mr.  Appleton  were  that 
inasmuch  as  the  committee  had  plainly  stated  that  a  certain 
sum  must  be  available  in  order  to  do  all  possible  toward 
extermination  in  one  year,  and  as  the  committee  was  required 
by  law  to  use  "all  possible  and  reasonable  measures"  to 
secure  the  extermination  of  the  moth,  and  as  with  the  $100,- 
000  the  committee  could  do  no  more,  in  his  opinion,  than  to 
continue  the  suppression  of  the  moth,  he  felt  it  incumbent 
upon  him  to  resign  rather  than  to  attempt  a  task  which  he 
believed  impossible  to  accomplish  with  a  less  sum  than  had 
been  recommended. 

As  the  committee  had  been  elected  by  the  Board  and  del- 
egated to  this  work,  and  as  the  Board  would  have  no  meeting 
during  the  spring  or  summer,  the  other  members  of  the  com- 
mittee considered  it  their  duty  to  do  all  that  was  possible 
with  the  appropriation  made,  and  report  the  result  to  the 
Board  at  its  next  annual  meeting  with  such  recommendations 
as  should  at  that  time  seem  best. 


78  THE  GYPSY  MOTH. 

On  June  19  the  executive  committee  of  the  State  Board  of 
Agriculture  petitioned  for  an  additional  appropriation  of 
$65,000,  but  the  petition  was  referred  by  the  Legislature 
to  the  next  General  Court. 

The  work  of  destroying  the  eggs  of  the  moth  had  been 
carried  on,  whenever  the  weather  permitted,  in  January, 
February,  March  and  April.  During  these  months  the  Leg- 
islature had  been  considering  the  advisability  of  making  the 
appropriation  recommended  by  the  committee  in  charge  of 
the  work.  On  March  6  the  committee  held  a  joint  meeting 
with  the  Metropolitan  Park  Commission.  Arrangements 
were  made  so  that  the  work  of  the  Board  of  Agriculture  in 
the  Middlesex  Fells  might  not  conflict  with  the  plans  of  the 
Park  Commission.  The  public  forest  reservation  controlled 
by  the  Park  Commission  and  situated  in  Maiden,  Medford, 
Melrose,  Stoneham  and  Winchester,  includes  most  of  the 
Middlesex  Fells. 

On  May  1,  the  appropriation  of  1893  having  been  ex- 
pended, all  field  work  was  discontinued.  Nothing  was  done 
hi  the  field  from  that  time  until  May  23,  when  the  Legis- 
lature appropriated  $100,000.  More  than  three  weeks  of 
the  best  working  time  of  the  season  were  thus  lost.  Those 
portions  of  the  infested  region  in  which  it  had  been  planned 
to  destroy  the  eggs  or  young  caterpillars  were  left  entirely 
unguarded  and  the  caterpillars  hatched  and  scattered  over 
the  surrounding  country.  Thus  the  delay  of  the  appropria- 
tion made  the  work  for  more  costly.  Trained  and  experi- 
enced employees  were  obliged  to  seek  positions  elsewhere, 
and  the  indirect  loss  and  delay  occasioned  were  as  detrimen- 
tal to  the  work  as  the  loss  of  time  when  the  men  were  laid 
off.  '  *  This  enforced  suspension  of  the  work  was  most  unfort- 
unate, occurring  as  it  did  when  the  men  were  destroying 
the  egg-clusters  at  the  rate  of  thousands  per  day.  Before 
work  was  resumed  the  remaining  eggs  had  hatched  and  the 
larvae  had  scattered.  Had  the  work  not  been  thus  inter- 
rupted, it  would  have  been  possible  in  many  places  to 
destroy  these  young  larvae  en  masse  by  means  of  burning."  * 


•  Fourth  Report  of  the  Bomrd  of  Agriculture  on  the  work  of  Extermination  of  the 
Gypsy  Moth,  January,  1S95. 


VISITS  OF  ENTOMOLOGISTS.  79 

As  soon  as  possible  after  the  appropriation  was  available 
all  those  experienced  and  trustworthy  men  who  could  be 
reached  were  re-employed.  The  trees  were  burlapped  and 
all  haste  made  to  prepare  the  infested  trees  for  the  summer 
work.  In  many  places  the  caterpillars  appeared  in  large 
numbers  and  it  required  the  work  of  the  entire  season  to 
hold  them  in  check. 

The  hatching  and  scattering  of  the  caterpillars,  which  the 
delay  of  the  appropriation  allowed,  necessitated  the  burlap- 
ping  of  a  greater  number  of  trees  and  the  employment  of  a 
larger  force  for  the  summer.  There  were  624,673  trees  bur- 
lapped  during  the  summer  and  265  men  were  of  necessity  em- 
ployed to  attend  the  burlaps.  The  result  was  the  destruction 
at  a  great  expense  of  a  great  number  of  caterpillars,  many  of 
which  would  not  have  existed  had  the  appropriation  been  made 
at  an  earlier  date.  A  large  part  of  the  appropriation  having 
been  used  in  burlapping  trees  and  killing  caterpillars  during 
the  summer,  it  became  necessary  to  discharge  a  large  part 
of  the  force  at  the  end  of  the  burlapping  season  on  August 
25.  Thirty-three  men  were  then  discharged  and  others 
were  discharged  in  September,  so  that  by  October  1  only 
133  men  remained.  This  force  was  entirely  insufficient  to 
inspect  thoroughly  the  220  square  miles  in  the  known,  infested 
region,  to  say  nothing  of  the  belt  of  territory  outside  of  it 
which  the  committee  believed  ought  to  be  inspected.  The 
men  were  kept  at  work  during  every  day  when  it  was  possi- 
ble to  work  to  advantage,  and  everything  was  done  that 
could  be  done  with  the  small  force  remaining  to  inspect  the 
outer  towns  of  the  infested  region.  It  was  found  necessary 
again  to  neglect  the  central  towns  to  a  certain  extent  that 
the  outer  towns  might  be  inspected  as  thoroughly  as  possible 
and  that  the  moth's  spreading  might  be  prevented. 

In  June  Dr.  George  H.  Perkins  of  the  University  of  Ver- 
mont, entomologist  of  the  Vermont  State  Agricultural  Ex- 
periment Station,  visited  the  infested  region  upon  invitation 
of  the  committee  and  inspected  the  work.  In  July  Prof.  F. 
L.  Harvey,  botanist  and  entomologist  of  the  Experiment 
Station  at  the  Maine  State  College,  Prof.  J.  Henry  Comstock 
of  Cornell  University,  formerly  United  States  entomologist, 
and  Mr.  L.  O.  Howard,  entomologist  of  the  United  States 


80  THE  GYPSY  MOTH. 

Department  of  Agriculture,  examined  the  infested  region 
and  inspected  the  work.  These  gentlemen  gave  the  com- 
mittee the  benefit  of  their  criticism  and  advice  in  the  field, 
and  Professors  Perkins,  Harvey  and  Comstock  made  written 
reports  to  the  committee.  (See  Appendix  E.) 

Mr.  Howard,  later,  in  his  annual  address  before  the  sixth 
annual  meeting  of  the  Association  of  Economic  Entomolo- 
gists, of  which  he  was  president,  gave  his  impressions  and 
opinions  of  the  work.  (See  Appendix  E.) 

During  the  summer  the  experiment  in  trapping  male 
moths  was  tried  on  a  larger  scale  than  in  1893.  While  many 
moths  were  destroyed,  the  results  as  a  whole  were  not  suc- 
cessful enough  to  warrant  the  adoption  of  the  method  in 
field  work.  Arsenate  of  lead  (first  experimented  with  in 
1893)  was  used  in  spraying  to  a  limited  extent  during  the 
spring.  While  more  effective  than  Paris  green,  it  was 
determined  that  it  could  not  be  depended  upon  to  exter- 
minate. 

The  fall  inspection  in  Boston  revealed  the  presence  of 
moths  in  three  sections  of  the  city  not  before  known  to  be 
infested — Roxbury,  Dorchester  and  the  city  proper.  One 
colony  was  found  in  each  section.  Two  of  them  had  been 
established  evidently  for  several  years,  but  the  demands  of 
the  work  elsewhere  had  hitherto  prevented  an  inspection  of 
this  large  territory. 

The  inspection  of  towns  which  had  been  apparently  cleared 
in  1893  revealed  a  few  egg-clusters  or  other  forms  of  the 
moth  in  all  of  them.  A  careful  search  of  a  portion  of  the 
unexplored  wooded  region  revealed  a  number  of  small  col' 
onies  in  the  Lynnfield  woods.  With  this  exception  very 
few  moths  were  found  in  any  of  these  towns.  The  discovery 
of  the  moths  in  these  towns  emphasized  the  necessity  of 
keeping  them  under  surveillance  for  a  few  years  after  they 
had  been  apparently  cleared  and  as  long  as  there  were  moths 
in  any  of  the  adjacent  towns. 

The  discovery  of  the  moths  in  the  Lynnfield  woods  verified 
the  prediction  which  the  committee  made  in  1893,  of  the 
probability  of  the  moth's  existence  in  the  wooded  region,  and 
showed  the  necessity  of  a  sufficient  appropriation  to  thor- 
oughly search  the  woodland.  The  committee  in  its  report 


CONDITION  OF  THE  REGION.  81 

to  the  Legislature  stated  the  condition  of  the  infested  region 
as  follows :  — 

In  ten  of  the  outer  towns  the  moth  has  been  apparently  extermi- 
nated ;  in  five  more  it  has  been  very  nearly  exterminated.  More 
than  a  thousand  well-marked  moth  colonies  have  been  stamped 
out  of  existence.  In  all  of  the  infested  towns  such  sections  as 
have  been  worked  over  year  after  year  by  the  employees  of  the 
State  Board  of  Agriculture  are  now  nearly  cleared  of  the  moth, 
and  the  general  condition  of  the  inhabited  and  cultivated  lands 
is  better  than  ever  before.  Against  this  favorable  condition  of 
such  portions  of  these  towns  we  must  place  the  fact  which  has 
been  revealed  by  the  inspection  of  the  past  season,  —  that  the 
woodlands  in  many  of  the  towns  are  much  more  generally  infested 
than  has  been  hitherto  supposed.  Scattered  colonies  of  the  moth 
are  known  in  the  woods  of  Lexington,  Winchester,  Arlington, 
Belmont,  Stoneham,  Medford,  Wakefield,  Melrose,  Maiden,  Lynn- 
field,  Saugus,  Revere,  Swampscott,  Lynn  and  Salem. 

This  condition  of  the  forested  lands  is  due  to  the  fact  that  there 
has  not  been  money  enough  to  provide  for  destruction  of  these 
colonies  whenever  found.  It  has  been  impossible,  with  the  means 
at  our  command,  to  make  a  thorough  search  of  all  this  woodland ; 
but  during  the  past  season  special  efforts  have  been  made  to  in- 
spect it  so  far  as  was  possible  under  the  circumstances,  and  enough 
is  now  known  to  justify  the  presumption  that  colonies  of  the  moth 
are  scattered  through  the  woods  from  Lexington  to  the  sea.  Though 
many  of  the  colonies  found  have  apparently  had  their  origin  within 
two  or  three  years,  many  others  originated  at  least  ten  years  since. 
The  woodland  which  is  thus  more  or  less  infested  probably  covers 
fifty  square  miles  of  the  central  and  north-central  portions  of  the 
infested  district. 

In  the  attempt  to  exterminate  the  gypsy  moth  it  was  early 
ascertained  that  the  species  was  spread  over  a  region  many  times 
greater  than  that  which  was  at  first  known  to  be  infested,  and  that 
it  was  not  confined  to  lands  under  cultivation,  but  had  penetrated 
to  some  extent  into  the  woodlands.  These  discoveries  made  it 
certain  that  extermination  would  be  extremely  difficult,  requiring 
years  for  accomplishment  even  under  the  most  favorable  condi- 
tions. The  best  methods  known  and  used  at  first  were  not  effect- 
ual in  securing  extermination,  and  the  methods  which  later  proved 
effective  were  so  expensive  that  they  could  not  be  carried  out  over 
so  large  an  area  without  larger  appropriations  than  those  which 
have  been  granted. 

Although  the  extent  of  the  infested  region,  the  existence  of  the 


82  THE  GYPSY  MOTH. 

moths  in  the  woods  and  the  great  expense  of  exterminative 
methods  have  been  all  repeatedly  presented  to  the  Legislature  in 
the  annual  reports  of  this  Board,  the  amount  appropriated  for 
each  of  the  past  two  years  has  been  only  about  two-thirds  of  that 
recommended  by  the  Board  as  absolutely  necessary  to  do  all  that 
could  be  done  to  advantage  under  the  circumstances. 

The  law  requires  the  Board  "  to  use  all  reasonable  measures  to 
prevent  the  spreading  and  to  secure  the  extermination "  of  the 
moth.  The  Board  has  apparently  been  successful  in  preventing 
the  spread  of  the  moth  and  has  considerably  lessened  the  area 
known  to  be  infested.  It  has  never  had  an  appropriation  suffi- 
ciently large  to  do  all  that  might  have  been  done  in  one  year  toward 
the  extermination  of  the  moth.  If  the  work  is  to  be  carried  on 
under  the  present  statute,  and  the  policy  of  extermination  is  to  be 
continued,  we  believe  that  two  hundred  thousand  dollars  should  be 
appropriated  for  the  work  of  the  coming  year. 

The  committee  believes  that  the  work  of  extermination  should 
be  continued,  but  is  also  firmly  of  the  opinion  that,  if  the  Legis- 
lature is  unwilling  to  appropriate  the  sum  necessary  for  an  aggres- 
sive campaign  for  extermination,  the  law  should  be  changed  so 
that  the  Board  of  Agriculture  shall  be  required  to  conduct  the 
work  only  along  the  line  of  preventing  the  spread  of  the  gypsy 
moth.  The  committee  further  believes  that,  if  the  Legislature  is 
unwilling  to  provide  sufficient  funds  for  restricting  the  spread  of 
the  gypsy  moth  and  holding  it  in  check,  the  work  should  be  dis- 
continued entirely.  The  committee  is  not  in  favor  of  appropri- 
ating inadequate  funds  for  the  work  in  hand.  It  seems  unjust 
to  require  the  extermination  of  the  pest  while  providing  inadequate 
means  for  the  purpose.  The  Board  of  Agriculture  has  recom- 
mended for  each  of  the  past  two  years  an  appropriation  of  one 
hundred  and  sixty-five  thousand  dollars,  believing  that  sum  was 
absolutely  required  for  the  successful  prosecution  of  the  work. 
The  Legislature  has  appropriated  only  one  hundred  thousand 
dollars,  or  about  sixty  per  cent,  of  the  sum  asked  for  each  of 
these  years.* 


*  Fourth  Report  of  the  State  Board  of  Agriculture  on  the  work  of  Extermination 
of  the  Gypsy  Moth,  January,  1895. 


PLATE  XIII.     Oak  and  pine  woods  attacked  by  the  gypsy  moth.    From 
photograph  taken  in  Lexington,  July  11,  1895. 


THE   WORK  OF   1895.  83 


THE    WORK    or    1895. 

The  Legislature  of  1894  had  adopted  a  resolve  request- 
ing the  senators  and  representatives  from  Massachusetts  in 
the  Congress  of  the  United  States  to  urge  upon  Congress  the 
necessity  of  prompt  and  vigorous  action  to  exterminate  the 
gypsy  moth,  and  to  use  their  influence  to  secure  from  Con- 
gress an  appropriation  of  one  hundred  thousand  dollars  to 
assist  this  Commonwealth  in  defraying  the  necessary  ex- 
penses of  the  work. 

The  Board  of  Agriculture  was  notified  by  the  agricultural 
committee  of  the  United  States  Senate  that  a  hearing  would 
be  given  on  Friday,  Jan.  4,  1895,  upon  the  resolve  presented 
by  the  Massachusetts  Legislature.  A  committee  consisting 
of  Francis  H.  Appleton,  vice-president,  and  Wm.  R.  Ses- 
sions, secretary,  of  the  Board  of  Agriculture,  accompanied 
by  the  director  of  field  work,  appeared  on  January  5  before 
the  Senate  committee  on  agriculture,  and  also  before  the 
committee  on  agriculture  of  the  United  States  House  of 
Representatives,  at  a  special  hearing  upon  a  resolution  in- 
troduced into  Congress  by  Hon.  William  Cogswell,  which 
provided  for  the  appropriation  asked  for  by  the  resolution 
of  the  Massachusetts  Legislature.  The  committee  also  pre- 
sented the  matter  to  Hon.  J.  Sterling  Morton,  secretary  of 
the  United  States  Department  of  Agriculture.  Later,  a  re- 
solve appropriating  forty  thousand  dollars  for  the  extermina- 
tion of  the  gypsy  moth  passed  the  United  States  Senate  but 
was  defeated  in  a  conference  committee  chosen  from  both 
houses. 

At  the  annual  meeting  of  the  Board  of  Agriculture,  Feb. 
6,  1895,  Mr.  Wm.  H.  Bowker,  a  member  of  the  committee 
on  the  gypsy  moth,  insects  and  birds,  retired  from  the  Board, 
his  term  having  expired  on  that  day.  Mr.  Bowker  had  been 
a  prominent  member  of  the  Board,  and  its  reorganization 
was  the  outcome  of  his  suggestions.  The  two  vacancies  in 
the  membership  of  the  committee,  left  by  the  resignation  in 
1894  of  Mr.  Appleton  and  the  retirement  of  Mr.  Bowker, 


84  THE   GYPSY  MOTH. 

were  filled  by  the  election  of  Messrs.  John  G.  A  very  of 
Spencer  and  S.  8.  Stetson  of  Lakeville. 

The  report  of  the  Board  of  Agriculture,  containing  a  recom- 
mendation for  an  appropriation  of  two  hundred  thousand  dol- 
lars, was  presented  to  the  legislative  committee  on  agriculture 
immediately  after  its  organization  in  January.  Some  oppo- 
sition to  the  appropriation  developed  in  the  committee,  and 
the  time  and  attention  of  the  members  were  occupied  for 
some  weeks  with  other  important  measures.  This  committee 
held  public  hearings  during  the  week  beginning  February  11, 
at  which  hundreds  of  citizens  from  the  infested  towns  were 
present.  The  preponderance  of  sentiment  was  in  favor  of 
granting  the  appropriation  asked  for.  On  March  21  the 
committee  finally  acted  upon  the  matter,  and  reported  a 
resolve  calling  for  an  appropriation  of  one  hundred  and  fifty 
thousand  dollars.  Although  this  amount  was  looked  upon 
by  the  Board  of  Agriculture  as  entirely  inadequate,  there 
appeared  to  be  fully  as  much  danger  to  the  work  by  delay  in 
making  the  appropriation  as  by  reduction  of  its  size.  The 
committee  on  the  gypsy  moth,  insects  and  birds  therefore 
endeavored  to  urge  upon  the  General  Court  the  immediate 
passage  of  the  bill  as  reported  by  the  committee  on  agri- 
culture. But  it  was  not  until  May  17  that  the  appropriation 
of  one  hundred  and  fifty  thousand  dollars  finally  became  avail- 
able. Early  in  the  year  the  appropriation  of  1894  was  nearly 
exhausted  and  on  February  6  the  field  force  was  discharged. 
The  work  of  destroying  the  eggs  of  the  moth,  which  should 
have  been  carried  on  during  the  spring  in  those  portions  of 
the  infested  towns  not  wholly  cleared  of  them  in  the  fall,  was 
thereby  brought  to  an  end.  Thus  the  experience  of  1894  was 
repeated,  but  the  amount  of  working  time  (three  months)  lost 
in  1895,  owing  to  the  lateness  of  the  appropriation,  was  much 
greater  than  in  the  previous  year.  The  discontinuance  of  the 
field  work  in  1895  was  especially  disastrous  because  occurring 
in  an  early  spring  which  later  developments  showed  was  par- 
ticularly favorable  for  the  moths'  increase.  The  great  mul- 
tiplication of  the  numbers  of  the  moth  which  occurred  during 
this  favorable  season,  their  scattering  abroad  and  the  con- 
sequent injury  to  trees  by  their  feeding,  might  have  been 
prevented  by  destroying  the  eggs  in  the  spring. 


PLATE  XIV.     Oak  trees  stripped  by  caterpillars  of  the  gypsy  moth,  Sar- 
gent Street,  Dorchester.    (Ward  16,  Boston.)    From  a 
photograph  taken  July  24,  1895. 


DELAY  IN  LEGISLATION.  85 

When  it  became  evident  that  there  would  be  considerable 
delay  in  legislation,  the  committee  authorized  the  director  to 
employ  as  a  nucleus  of  an  organization  such  experienced  men 
as  were  willing  to  wait  for  their  pay  until  such  time  as  the 
Legislature  should  make  an  appropriation.  The  office  force 
was  employed ;  the  records  were  closed  up  ;  examinations  of 
applicants  for  positions  on  the  force  were  begun ;  arrange- 
ments were  made  for  the  purchase  of  supplies ;  and  other 
preliminaries,  providing  for  the  early  employment  of  a  full 
force  of  men,  were  arranged.  When  the  appropriation 
became  available,  it  was  too  late  in  the  season  to  accom- 
plish much  by  the  destruction  of  eggs,  for  most  of  them  had 
hatched.  As  the  men  were  put  at  work,  those  who  were 
inexperienced  were  given  a  week  or  more  of  training  in 
clearing  up  infested  woodlands  and  cutting  and  burning 
brush.  They  were  then  organized  into  burlapping  gangs 
and  employed  in  placing  burlap  bands  around  the  trees  in 
infested  localities. 

It  was  found  necessary  to  increase  the  force  as  rapidly  as 
the  careful  selection  and  examination  of  men  allowed,  for  the 
caterpillars  of  the  moth  were  appearing  numerously  wherever 
the  egg-clusters  had  not  been  destroyed.  As  the  season 
advanced  the  great  increase  in  the  numbers  of  the  moth  was 
noticeable.  More  men  than  were  ever  before  employed  in 
the  work  were  engaged  to  meet  the  emergency.  On  July 
20  three  hundred  and  fifty  men  were  at  work,  and  even  with 
this  force  it  was  not  possible  to  prevent  occasional  injury  to 
foliage  in  certain  places.  A  swarm  of  caterpillars  appeared 
in  one  locality  in  Dorchester,  within  a  few  rods  of  the  point 
where  the  inspection  of  the  winter  previous  had  ceased  on 
account  of  snow.  Many  of  the  trees  in  an  oak  grove  were 
defoliated  before  the  presence  of  the  caterpillars  was  dis- 
covered. Immediate  steps  were  taken  to  destroy  them  and 
in  a  short  time  some  eighteen  bushels  of  caterpillars  were 
killed  in  this  locality. 

Various  points  in  the  woods  of  Lexington  and  Woburn 
were  found  to  be  swarming  with  the  caterpillars  of  the  gypsy 
moth.  Here  they  defoliated  several  acres  of  woodland. 
Later  in  the  season  similar  colonies  were  discovered  in  the 
woods  of  Medford,  one  being  situated  in  the  southern  por- 


86  THE  GYPSY  MOTH. 

tion  of  the  metropolitan  park  reservation  known  as  the 
Middlesex  Fells.  Others  were  found  in  the  Saugus  woods. 
In  some  of  the  localities  where  the  moth  appeared  in  num- 
bers in  the  woods  the  injury  extended  over  from  one  to 
three  acres,  leaving  the  trees  as  bare  as  in  winter. 

Wherever  the  forest  was  defoliated  in  this  manner  the 
infested  trees  presented  from  a  distance  the  appearance  of 
having  been  killed  by  fire.  These  reddish  patches  on  the 
hillsides  stood  out  strongly  in  contrast  with  the  green  of  the 
summer  foliage  by  which  they  were  surrounded.  On  enter- 
ing one  of  these  infested  spots  during  the  time  when  the 
caterpillars  were  feeding,  one  was  immediately  struck  by  the 
rustling  sound  caused  by  their  movements  and  the  falling  of 
their  droppings  and  the  bits  of  foliage  wrhich  they  were  con- 
tinually cutting  from  the  leaves.  A  little  later  in  the  season, 
during  the  warmer  part  of  the  day,  the  male  moths  fluttered 
in  swarms  about  the  trees  while  the  white  females  were  scat- 
tered over  the  trunks  and  branches  of  trees  and  upon  the  dry 
leaves  on  the  ground. 

Nearly  all  species  of  trees  and  most  herbaceous  plants  in 
this  badly  infested  woodland  were  stripped  by  the  caterpil- 
lars. In  some  places  they  ate  the  foliage  of  the  pines,  both 
young  and  old.  Some  of  these  trees  appear  now  to  be  dy- 
ing. But  on  account  of  the  unusually  rapid  development  of 
the  moths  this  season,  their  consequent  maturing  and  ces- 
sation of  feeding,  the  trees  were  not  continually  stripped 
throughout  the  summer ;  therefore  the  deciduous  trees  began 
to  throw  out  new  foliage  late  in  July  and  early  in  August, 
when  the  female  moths  were  laying  their  eggs.  This  rapid 
development  of  the  moths  during  the  past  season  appears  to 
be  unprecedented  in  this  country  so  far  as  can  be  ascertained. 
As  the  probable  result,  a  second  brood  of  the  moths  appeared 
in  one  locality  in  Woburn.  Young  caterpillars  were  found 
leaving  the  egg-clusters  in  the  first  weeks  of  September. 
As  the  summer  waned,  many  localities  in  the  woods  were 
found  where  the  egg-clusters  of  the  moth  were  quite  numer- 
ous, bidding  fair,  if  not  destroyed,  to  produce  a  brood  of 
caterpillars  during  1896  which  may  prove  even  more  de- 
structive than  those  of  the  present  season. 

This  condition  of  affairs  fulfilled  the  predictions  which  the 


PLATE  XV.     Woodland  colony  of  the  gypsy  moth  as  seen  at  a  distance  of 
one-third  of  a  mile.    The  light  area  in  the  woods  in  the  background 
shows  the  appearance  of  a  defoliated  tract  as  compared  with 
the  surrounding  uninfested  trees.    From  a  photo- 
graph taken  in  Woburn,  July  19,  1895. 


THE  WOODS  INFESTED.  87 

committee  made  to  the  Legislature  in  former  years,  namely, 
that  the  moths  were  distributed  generally  through  the  wood- 
land in  the  inner  towns  of  the  infested  region,  and  demon- 
strated that  they  might  prove  a  serious  danger  to  wooded 
parks  and  forests.  Experts  were  sent  into  the  woods  to 
examine  them  as  thoroughly  as  was  possible  during  the 
summer.  They  discovered  that  a  large  portion  of  the  Mid- 
dlesex Fells  was  more  or  less  infested  by  the  moth.  At 
least  one  thousand  acres  of  this  reservation  now  appear  to 
be  in  this  condition.  In  Saugus  a  tract  of  about  the  same 
size  appears  to  be  similarly  affected,  and  another  even  larger, 
situated  in  Woburn,  Lexington  and  Arlington,  is  also  more 
or  less  infested.  There  are  at  least  three  thousand  acres  of 
woodland  in  the  foregoing  towns  that  are  now  known  to  be 
infested  by  the  gypsy  moth.  This  condition  had  been  sus- 
pected, but  the  appropriation  had  never  been  sufficient  to 
watch  the  cultivated  lands  and  highways  and  also  to  care 
for  the  forested  region. 

Throughout  the  season  of  1895,  as  in  previous  seasons, 
experiments  on  insecticides  were  conducted  in  the  field  and 
observations  were  made  on  the  habits  of  the  moth  and  its 
enemies.  A  small  building  was  erected  in  the  Maiden 
woods  for  use  as  an  experiment  station,  and  to  facilitate  the 
breeding  of  parasites  and  predaceous  insects  to  be  used  for 
experimental  purposes.  In  all  probability  the  results  ob- 
tained from  observations  and  experiments  in  1895  are  more 
valuable  than  those  of  former  years.  The  experiments  and 
their  results  are  treated  of  in  the  report  of  the  entomologist. 

In  some  localities,  where  the  moths  were  numerous  upon 
valuable  ornamental  shrubs  or  trees,  the  foliage  was  sprayed 
with  arsenate  of  lead.  Where  it  was  used  at  a  strength  of 
thirty  pounds  to  one  hundred  and  fifty  gallons  of  water  all 
the  caterpillars  appeared  to  be  destroyed. 

During  the  season  fire  was  used  with  good  effect  in  many 
cases  to  check  the  ravages  of  the  caterpillars  in  waste  land. 

At  the  time  of  going  to  press  little  can  be  said  of  the 
results  of  the  work  of  1895.  It  may  be  predicted,  however, 
that  considering  the  phenomenal  increase  of  the  moths  in 
those  sections  where  egg  killing  was  not  done  in  the  spring 
because  of  the  delay  of  the  appropriation,  and  considering 


88  THE   GYPSY  MOTH. 

also  the  large  number  of  men  employed  later,  the  results 
of  the  season's  work  will  show  a  greater  number  of  the  dif- 
ferent forms  of  the  moth  destroyed  than  at  any  time  since 
1891. 

We  have  long  feared  that  unless  appropriations  suffi- 
cient for  complete  eradication  were  granted,  some  favorable 
season  might  give  the  moths  a  sudden  impetus  which  would 
cause  them  to  increase  beyond  immediate  control.  Such  an 
emergency  has  arisen,  and  in  the  centres  of  population,  in 
cultivated  lands  and  along  the  highways,  it  has  been  fully  met. 
It  is  true  that  in  the  woodland  where  the  greatest  infestation 
occurred  some  injury  was  done  for  a  time  by  the  moths,  but, 
in  such  places,  they  are  now  under  control,  and  with  vigor- 
ous measures  they  may  be  entirely  exterminated  from  these 
localities  within  two  or  three  years.  Yet  there  is  a  large 
wooded  region  in  the  north-central  towns  which  never  has 
been  thoroughly  cared  for  and  never  can  be  unless  larger 
appropriations  are  made.  In  many  portions  of  this  wood- 
land the  moths  are  doubtless  steadily  increasing  in  numbers, 
and  all  that  has  been  done  or  can  be  done  there,  with  the 
means  thus  far  furnished  by  the  Commonwealth,  is  to  check 
them  whenever  they  appear  in  such  numbers  as  to  threaten 
serious  injury  to  the  trees. 

The  results  of  the  work  of  1895  will  be  presented  in  the 
next  annual  report  to  the  Legislature. 


NUMBER  OF  EMPLOYEES. 


89 


THE   NUMBER   OF  MEN  EMPLOYED  AND  WORK 
DONE,  1890  TO  1894  INCLUSIVE. 

In  order  to  give  an  opportunity  for  comparing  the  number 
of  employees  and  the  amount  of  work  done  each  year  we 
give  tables  taken  from  the  pay-rolls  of  1890  and  the  reports 
of  the  years  1891  to  1894  inclusive  :  — 

1890. 


DATE. 

Number  of 
Men. 

DATK. 

Number  of 
Men. 

Mar.  24-29,     . 

27 

Aug.    4-  9,    . 

7 

"     31-April  5, 

57 

"     11-16,     . 

- 

April    7-12,     . 

74 

"     18-23,    . 

- 

"      14-19,     . 

62 

"    25-30,    . 

— 

"     21-26,     . 

59 

Sept.    1-  6,    . 

- 

«     28-May  3, 
May     5-10,     . 

51 
53 

"      8-13,    . 
"     15-20,    . 

2 
2 

"      12-17,     . 

36 

"     22-27,    . 

4 

"      19-24,     . 

65 

"    29-Oct.  4, 

5 

"     26-31,     . 

72 

Oct.     6-11,    . 

7 

June     2-  7,     . 

76 

"     13-18,    . 

5 

"       9-14,     . 

88 

"     20-25,    . 

18 

"      16-21,     . 

89 

"     27-Nov.  1, 

40 

«     23-28,     . 

89 

Nov.    3-  8,    . 

25 

"     30-July  5, 
July      7-12,     . 

84 

79 

"     10-15,    . 
"     17-22,    . 

28 
28 

"      14-19,     . 

80 

"     24-29,    . 

80 

"     21-26,     . 

42 

Dec.    1-  6,    . 

29 

"     28-Aug.  2, 

9 

1891. 


Mar.  20,  21,     . 

16 

June  22-27,   . 

217 

"     23-28,     . 

40 

"     29-July  4, 

209 

"     30-April  4, 
April    5-11,     . 
"      13-18,     . 
"     20-25,     . 

103 
129 
140 
146 

July     6-11,   . 
«      13-18,   .. 
"     20-25,   . 
"     27-Aug.  1, 

192 
170 
104 
106 

"     26-May  2, 
May     4-  9,     . 

167 
173 
199 

Aug.     3-  8,    . 
"      10-15,   . 
'      17-22,   . 

99 
98 
96 

"      18-23^     '. 

195 

'     24-29,   . 

88 

"      25-30,     . 
June     1-  6,     . 
"       8-13,     . 

211 
238 
242 

Se 

'     31-Sept.  5, 
pt.    7-12,   . 
«     14-19,    . 

83 
75 
78 

"      14-20,     . 

211 

'     21-26,   .        .        • 

67 

90 


THE  GYPSY  MOTH 


18  91  —  Concluded. 


DATK. 

Number  of 
Men. 

DATE. 

Number  of 

Sept.  28-Oct.  3 

62 

Nov.  16-21,   . 

45 

Oct.      5-10, 

58 

"     23-28,   . 

43 

i     "     12-17, 

58 

"     30-Dec.  5,     . 

41 

'     "      19-24, 

61 

Dec.     7-12,   . 

41 

"     26-31, 

59 

"      14-19,   . 

42 

Nov.     2-7,              . 

44 

"      21-26,    . 

42 

"       9-14, 

44 

"     28-Jan.  2,     . 

42 

1892. 


Jan.   4-  9,  .    . 

46 

July  4-  9,  . 

95 

"   11-16,  . 

46 

"   11-16,  . 

102 

"  18-23,  .   , 

47 

"  18-23,  . 

120 

"   25-30,  . 

48 

"  25-30,  . 

120 

Feb.  1-  6,  . 

48 

Aug.  1-  6,  . 

126 

"   8-13,  . 

48 

"   8-13,  . 

129 

"   15-20,  . 

31 

"  15-20,  . 

122 

"  22-27,  . 

68 

"  22-27,  . 

107 

"  29-Mar.  5,   . 

88 

"  29-Sept.  3, 

107 

Mar.  7-12,  . 

111 

Sept.  5-10,  . 

97 

"   14-19,  . 

127 

"   12-17,  . 

95 

"  21-26,  . 

141 

"  19-24,  . 

37 

"  28-April2,  . 
April  4-  9,  . 

191 
219 

"  26-30,  . 
Oct.   3-  8,  . 

33 

38 

"   11-16,  . 

234 

"   10-15,  . 

36 

"  18-23,  . 

233 

"  17-22,  . 

37 

"  25-30,  . 

230 

"  24-29,  . 

37 

May  2-  7,  . 

232 

"  31-Nov.  5, 

38 

"   9-14,  .    .    . 

183 

Nov.  7-32,  . 

38 

"  16-21,  . 

140  • 

"  14-19,  . 

37 

"  23-28,  . 

140 

"  21-26,  . 

34 

"  30-June4,   . 

91 

"  28-Dec.  3, 

36 

June  6-11,  . 

90 

Dec.  5-10,  . 

36 

"   13-18,  . 

87 

"  12-17,  . 

35 

"  20-25,  . 
"  27-July2,   . 

89 
93 

"  19-24,  . 
"  26-31,  . 

34 
33 

1893. 


Jan.      2-  7, 

30 

Mar.  20-25,   . 

8 

"       9-14, 

.        . 

28 

"      27-April  1, 

27 

"      16-21, 

28 

April    3-  8,    . 

44 

"      23-28, 

.        • 

27 

"      10-15,   . 

93 

"     29-Feb. 

4,       . 

25 

"      17-22,    . 

115 

Feb.     6-11, 

. 

24 

"      24-29,   . 

125 

"     13-18, 

.        •        • 

24 

May     1-  6,   . 

128 

"     20-25, 

.        •        . 

22 

"       8-13,   . 

132 

"     27-Mar. 

4,       . 

25 

"      15-20,   . 

132 

Mar.     6-11, 

25 

"     22-27,    . 

132 

"     13-18, 

. 

" 

"     29-June  3, 

131 

NUMBER   OF  EMPLOYEES. 


91 


1893  —  Concluded. 


DATE. 

Number  of 
Men. 

DATE. 

Number  of 
Men. 

June  5-10,  . 

128 

Sept.  18-23,  . 

93 

"  12-17,  . 

131 

"  25-30,  . 

89 

"   19-24,  . 

132 

Oct.   2-  7,  . 

86 

"  26-Julyl,   . 

149 

"   9-14,  . 

85 

July  3-  8,  .   . 

153 

"   16-21,  . 

89 

"   10-15,  . 

154 

"  23-28,  . 

88 

"  17-22,  . 

147 

"  30-Nov.  4,  . 

88 

"  24-29,  . 

151 

Nov.  6-11,  . 

88 

"  3l-Aug.  5, 

146 

"   13-18,  . 

88 

Aug.  7-12,  . 

144 

"  20-25,  . 

85 

"   14-19,  . 

126 

"  27-Dec.  2,  . 

85 

"  21-26,  . 

125 

Dec.  4-  9,  . 

85 

"  28-Sept.  2,   . 

121 

"   11-16,  . 

86 

Sept.  4-  9,  . 

101 

"  18-23,  . 

85 

"  11-16,  . 

95 

"  25-30,  . 

83 

1894. 


Jan.   1-  6,  . 

82 

June  25-30,  . 

261 

"   8-13,  . 

86 

July  2-  7,  . 

265 

"   15-20,  . 

. 

85 

9-14,  . 

. 

270 

'  "  22-27,  . 

86 

"   16-21,  . 

265 

"  29-Feb.  3, 

83 

"  23-28,  . 

270 

Feb.  5-10,  . 

, 

82 

"  30-Aug.  4, 

261 

"   12-13,  . 

82 

Aug.  6-11,  . 

. 

266 

"   14-17,  . 

23 

"   13-18,  . 

. 

260 

"   19-24,  . 

81 

"  20-25,  . 

t 

216 

"  26-Mtir.  3, 

81 

"  27-Sept.  1, 

, 

15 

Mar.  5-10,  . 

•  . 

82 

Sept.  3-  8,  . 

. 

16 

"  12-17,  . 

. 

84 

"  10-15,  . 

147 

"   19-24,  . 

. 

85 

"   17-22,  . 

. 

148 

"  26-31,  . 

91 

"  24-29,  . 

. 

133 

April  2-  7,  . 

95 

Oct.   1-  6,  . 

133 

"   9-14,  . 

,  . 

121 

"   8-13,  . 

. 

131 

"  16-21,  . 

157 

"  15-20,  . 

. 

123 

"  23-28,  . 

. 

159 

"  22-27,  . 

125 

"  30-May  1, 

. 

156 

"  29-Nov.  3,  ' 

128 

May  2-  9,  . 

. 

15 

Nov.  5-10,  . 

128 

"  10-12,  . 

. 

164 

"  12-17,  . 

. 

133 

"  14-19,  . 

173 

"  19-24,  . 

133 

"  21-26,  . 

,  - 

213 

"  26-Dec.  1, 

, 

132 

"  28-June  2, 

228- 

Dec.  3-  8,  . 

132 

June  4-  9,  . 

230 

"  10-15,  . 

134 

"   11-16,  V  . 

, 

229 

"   17-22,  . 

, 

135 

"   18-23,  .  ; 

225 

"  24-29,  . 

132 

Summary  of  Work  done  during  Four  Years. 
During  the  year  1890  no  account  of  the  number  of  dif- 
ferent forms  of  the  moth  destroyed  was  kept  by  the  first 


92 


THE  GYPSY  MOTH. 


commission,  and  the  reports  of  the  work  are  not  in  a  form 
that  can  be  used  in  making  tables  of  the  kind  given  below. 
It  would  have  been  almost  impossible  to  keep  any  accurate 
account  of  the  immense  numbers  of  the  moth  destroyed 
during  1890.  This  was  also  true  of  the  first  few  months  of 
1891.  Therefore  no  figures  or  estimates  of  the  numbers 
killed  during  those  years  are  given  in  the  tables.  The 
egg-clusters  destroyed  during  the  first  weeks  of  1891  were 
estimated  at  eight  cart-loads.  During  the  latter  part  of 
that  year  a  systematic  account  was  kept  of  the  number  of  the 
diiferent  forms  of  the  moth  found  on  each  infested  estate,  and 
from  that  and  the  other  accounts  of  the  season,  a  somewhat 
incomplete  table  of  the  work  of  1891  has  been  made.  A 
fuller  account  is  given  of  the  work  of  the  succeeding  years. 
Yet  even  this  summary  cannot  be  considered  as  complete, 
for  the  tables  pertain  mainly  to  the  hand  work  done  annually, 
and  only  such  figures  are  given  as  from  their  nature  can  be 
accurately  recorded.  Obviously  no  account  could  be  kept 
of  the  number  of  moths  destroyed  by  spraying,  fire  and  other 
wholesale  measures. 

It  will  be  seen  that  though  a  larger  number  of  men  was 
employed  in  1893  and  1894  than  in  1892,  fewer  trees  were 
found  infested  in  the  later  years,  although  the  number  of 
the  different  forms  of  the  moth  killed  by  hand  was  larger. 
This  may  be  chiefly  accounted  for  by  the  extension  of  the 
work  into  woodlands  in  the  inner  towns,  where  the  moths 
had  increased  unmolested.  In  badly  infested  places  in  the 
woods  the  number  of  moths  per  tree  was  very  great.  Many 
caterpillars,  pupae  and  egg-clusters  were  destroyed  in  bushes 
and  young  growth.  This  greatly  swelled  the  sum  total  of 
forms  of  the  moth  destroyed.  The  larger  appropriation  of 
1894  made  this  woodland  work  possible. 


1891. 

1898. 

1893. 

1894. 

Trees  (fruit,  shade  and  forest)  :  — 

3,591,982 

2  109,852 

4,108  494 

6  828  229 

Found  to  be  infested  with  caterpillars, 
pupa;,  moths  or  eggs  
Cleared  of  eggs,        

213,828 
212,432 
19  296 

108,428 
99,989 
12  172 

44,716 
2,068 
4  583 

48,752 
2,176 
7  844 

Banded  (insect  lime  or  tree  Ink),     . 

12,000 

21,251 

19,453 

SUMMARY  OF  WORK. 


93 


1891. 

1892. 

1893. 

1894. 

Trees  (fruit,  shade  and  forest)  —Con. 
Burlapped  

68,720 
177  415 

110,108 
7  372 

419,434 
5  145 

624,673 
14  857 

Trimmed,  ...... 

1  906 

8  618 

2  406 

6  068 

Cut             ... 

395 

4055 

10296 

Acres  of  brush  land  and  woodland  cut 

120 

115 

184 

336| 

Buildings:  — 

87  536 

22  102 

8  828 

27  430 

Found  to  be  infested,        .... 

3,647 
3  574 

1,557 
1  427 

348 
232 

508 
55 

Wooden  fences:  — 

53  219 

24  936 

15092 

35276 

Found  to  be  infested,        .... 

6,808 
6,570 

2,365 
2,159 

713 
541 

'798 
99 

Stone  walls  :  — 

2  213 

814 

1  620 

'672 

225 

'423 

354 

93 

44 

Number  of  each  form  of  the  moth  destroyed 
by  hand  ;  — 

935  656 

1  173  351 

1  153  560 

80  021 

77  029 

92*225 

Moths'  

9*338 

5655 

18  084 

Hatched  or  infertile  egg-clusters, 
Unhatched    and    probably   fertile   egg- 

- 

40,954 
99  790 

6,868 
46  101 

18,036 
94  706 

94  THE   GYPSY  MOTH. 


THE    INCREASE   AND    DISTRIBUTION   OF 
THE   GYPSY   MOTH. 

THE  RATE  or  INCREASE. 

The  study  of  the  increase  and  dissemination  of  the  gypsy 
moth  in  Massachusetts  is  most  interesting.  Perhaps  there 
never  has  been  a  case  where  the  origin  and  advance  of  an 
insect  invasion  could  be  more  readily  traced.  As  the  moth 
appears  to  be  confined  as  yet  to  a  comparatively  small  area, 
and  as  the  region  has  been  examined  more  or  less  thoroughly 
for  five  successive  years,  the  opportunities  offered  for  the 
study  of  the  multiplication  and  distribution  of  the  insect 
have  been  unequalled. 

When  it  is  considered  that  the  number  of  eggs  deposited 
by  the  female  averages  from  450  to  600,  that  1,000  cater- 
pillars have  been  seen  to  hatch  from  a  single  egg-cluster, 
and  that  at  least  one  egg-cluster  has  been  found  containing 
over  1,400  eggs,  there  can  be  no  doubt  that  the  reproductive 
powers  of  the  moth  are  enormous.  Mr.  A.  H.  Kirkland  has 
made  calculations  which  show  that  in  eight  years  the  unre- 
stricted increase  of  a  single  pair  of  gypsy  moths  would  be 
sufficient  to  devour  all  vegetation  in  the  United  States.  This, 
of  course,  could  never  occur  in  nature,  and  is  mentioned 
here  merely  to  give  an  idea  of  the  reproductive  capacity  of 
the  insect. 

It  seems  remarkable  at  first  sight  that  an  insect  of  such 
reproductive  powers,  which  had  been  in  existence  in  the  State 
for  twenty  years,  unrestrained  by  any  organized  effort  on  the 
part  of  man,  did  not  spread  over  a  greater  territory  than 
thirty  townships,  or  about  two  hundred  and  twenty  square 
miles.  Some  of  the  causes  which  at  first  checked  its  increase 
and  limited  its  diffusion  in  Medford  have  already  been  set 
forth  (pages  5-7 ) .  Most  of  the  checks  which  at  first  served 
to  prevent  the  excessive  multiplication  of  the  gypsy  moth  in 
Medford  operate  effectively  to-day  wherever  the  species  is  iso- 
lated. True,  it  has  now  become  acclimated.  But  any  small 
isolated  moth  colony  still  suffers  greatly  from  the  attacks 


ITS  RATE  OF  INCREASE.  95 

of  its  natural  enemies  and  from  the  struggle  with  other 
adverse  influences  which  encompass  it.  The  normal  rate  of 
increase  in  such  isolated  colonies  as  are  found  to-day  in 
the  outer  towns  of  the  infested  district  is  seen  to  be  small. 
The  annual  increase  can  be  readily  ascertained  by  noting 
the  relative  number  of  egg-clusters  laid  in  successive  years, 
the  unhatched  or  latest  clusters  being  easily  distinguished 
from  the  hatched  or  "old"  clusters,  and  the  age  of  these 
latter,  whether  one,  two,  three  or  more  years,  being  indi- 
cated by  their  state  of  preservation.  The  ratio  of  the  aver- 
age annual  increase  of  ten  such  colonies  was  found  to  be 
6.42,  — that  is,  six  or  seven  egg-clusters  on  an  average  may 
be  found  in  the  second  season  to  one  of  the  first  season. 

Though  even  at  this  rate  of  increase  the  progeny  of  a 
single  pair  of  moths  would  be  numerically  enormous  within 
twenty  years,*  yet  for  the  first  few  years,  under  normal  con- 
ditions, the  increase  of  a  small  and  isolated  moth  colony  is 
not  great  enough  to  work  any  serious  or  extended  injury. 
The  great  army  of  moths  does  not  advance  rapidly  by  the 
skirmish  line,  as  it  were,  but  only  by  the  main  body,  for  a 
great  increase  and  rapid  spread  to  a  distance  can  only  occur 
where  the  moths  have  become  so  numerous  over  a  consider- 
able area  as  to  have  nearly  reached  the  limit  of  their  food 
supply. 

Conditions  favoring  Rapid  Increase, 
When  any  colony  under  average  normal  conditions  has 
grown  to  a  considerable  size  and  then  receives  an  added 
impetus  from  exceptionally  favorable  conditions,  its  power 
of  multiplication  and  its  expansive  energy  are  greatly  aug- 
mented and  its  annual  increase  rises  above  all  calculations.! 
Under  such  influences  hundreds  of  egg-clusters  will  appear 
in  the  fall  where  few  were  to  be  seen  in  the  spring,  and 
thousands  are  found  where  scores  only  were  known  before. 
It  is  probable  that  the  season  of  1889  was  particularly  favor- 


*  At  this  ratio  the  number  of  egg-clusters  produced  in  the  twentieth  year  would  be 
14,148,179,507,899,404. 

t  The  increase  of  these  large  colonies  seems  to  be  limited  only  by  the  supply  of  food. 
Whenever  food  becomes  scarce  many  of  the  moths  are  less  prolific.  The  larvae  which 
do  not  find  sufficient  food  either  die  or  develop  early,  and  the  female  moths  lay  fewer 
eggs  than  those  which  transform  from  well-nourished  caterpillars. 


96  THE   GYPSY  MOTH. 

able  for  the  moths'  increase.  The  season  of  1894  and  that 
of  1895  appear  also  to  have  furnished  conditions  especially 
favorable  for  an  abnormal  multiplication  of  the  insect. 

The  operation  of  the  causes  of  these  sudden  outbreaks 
is  not  fully  understood.  It  is  evident,  however,  that  the 
warm,  pleasant  spring  weather  of  the  past  two  years  (1894 
and  1895)  hastened  the  development  of  the  caterpillars, 
thereby  shortening  their  term  of  life.  The  length  of  life  of 
the  caterpillar  varies  from  six  to  twelve  weeks.  During  cold, 
rainy  weather  the  caterpillars  eat  little  and  grow  slowly. 
During  warm,  dry  weather  they  consume  much  more  food 
and  grow  with  great  rapidity.  In  the  unusually  warm 
spring  and  early  summer  of  1895  many  of  the  caterpillars 
moulted  a  less  number  of  times  than  usual,  and  their  length 
of  life  did  not  exceed  six  or  seven  weeks.  Under  these 
conditions  they  proved  more  quickly  injurious  to  foliage 
than  in  a  more  normal  season,  and  were  more  completely 
destructive  within  any  given  area  in  which  their  numbers 
were  great.  And  they  were  not  so  long  exposed  to  the 
attacks  of  their  enemies.  While  it  may  be  true  that  the 
parasitic  enemies  of  the  moth  will  also  develop  rapidly 
under  conditions  that  hasten  the  growth  of  their  host,  birds 
and  other  vertebrate  enemies  will  secure  fewer  of  the  moths 
in  six  or  seven  weeks  than  in  ten  or  twelve.  This  would 
probably  be  true  of  many  predaceous  insects.  It  is  believed 
that  dry  weather  is  unfavorable  for  vegetable  parasites  of 
insects,  but  to  what  extent  the  caterpillars  are  affected  by 
them  in  a  humid  season  it  is  impossible  to  say. 

The  past  two  years  have  been  "  canker  worm  years"  in 
the  infested  region.  Many  of  the  birds  which  habitually 
feed  on  the  caterpillars  of  the  gypsy  moth  have  been  largely 
occupied  during  May  and  the  early  part  of  June  in  catch- 
ing canker  worms,  which  they  seem  to  prefer,  turning  their 
attention  to  the  gypsy-moth  caterpillars  in  the  latter  part 
of  June  and  July,  when  the  canker  worms  have  disappeared. 
The  birds,  therefore,  have  not  been  as  useful  in  checking  the 
increase  of  the  gypsy  moth  as  in  years  when  the  canker  worms 
were  less  numerous. 

A  few  of  the  restraining  influences  which  have  been  less 
active  than  usual  during  the  past  two  years  have  been  men- 


CONDITIONS   FAVORING  INCREASE.  97 

tioned,  and  possibly  many  others  have  escaped  observation, 
but  those  given  may  serve  in  a  measure  to  explain  the  un- 
usual increase  of  the  moth.  It  is  during  such  seasons  that 
its  destructiveness  is  most  apparent.  It  is  then  that  the 
groves  and  forests  are  stripped  of  their  leaves,  and  whole 
rows  of  trees  in  orchards  and  along  highways  appear  to  have 
been  stripped  in  a  single  night. 

DISTRIBUTION  AS  AFFECTED    BY  FOOD  SUPPLY  AND  OTHER 
NATURAL   CAUSES. 

If  the  number  of  gypsy-moth  larvae  in  a  given  territory 
is  small  and  their  food  supply  is  large,  they  do  not  usually 
spread  of  their  own  volition  to  any  appreciable  extent.  So 
long  as  the  supply  of  food  is  abundant  and  accessible  the 
caterpillars  usually  remain  on  or  near  it,  and  will  move  only 
when  disturbed  or  dislodged  from  the  trees  or  other  plants 
on  which  they  feed.  In  such  cases  they  will  reascend  the 
same  tree  or  crawl  to  near-by  vegetation.  When  a  tree  is 
overcrowded  with  caterpillars,  and  by  reason  of  their  vo- 
racity food  becomes  scarce,  they  will  crawl  rapidly  in  all 
directions  in  search  of  it,  and  thus  they  spread  out  from  a 
common  centre  over  a  limited  area.  Wherever  the  moth  is 
introduced  it  has  the  advantage  of  such  species  as  the  canker 
worms  (Paleacrita  vernata  and  Anisopteryx  pometaria)  and 
the  tent  caterpillar  (  Clisiocampa  americana) ,  which  are  con- 
fined to  a  few  kinds  of  food  plants.  Because  of  the  great 
number  of  its  food  plants  it  is  capable  of  subsisting  in  almost 
any  locality  whereto  it  may  migrate  or  be  transported.  Its 
spreading  is,  therefore,  more  general  and  its  distribution  less 
localized  than  that  of  the  canker  worms.  But  as  the  female 
moth  does  not  fly,  the  species  is  limited  in  its  powers  of 
migration,  and  though  the  larger  caterpillars  are  very  rest- 
less, their  movements  show  little  method  except  when  food 
becomes  scarce.  It  has  been  seen  that  isolated  colonies  of 
the  moth  in  woodlands  not  frequented  by  men  do  not  often 
spread  to  a  considerable  extent  until  the  caterpillars  have 
increased  in  numbers  so  as  to  destroy  all  the  foliage  in  the 
originally  infested  localities.  They  then  migrate  in  search 
of  food,  and  when  this  movement  is  once  begun  they  some- 


98^  THE   GYPSY  MOTH. 

times  scatter  to  a  considerable  distance.  Though  this  is  the 
rule  there  are  some  exceptions.  In  some  localities,  presum- 
ably where  the  larvae  are  persecuted  by  many  enemies,  they 
are  found  scattered  abroad  over  a  considerable  area  even 
when  food  is  abundant. 

The  moths  are  sometimes  distributed  by  birds.  Many 
birds  feed  upon  the  caterpillars,  and  in  some  cases  they  have 
been  known  to  drop  them  alive  while  carrying  them  to  their 
young.  As  the  larvse  are  very  hardy  and  are  likely  to 
survive  rough  treatment,  they  may  be  scattered  somewhat 
in  this  way.  Some  of  the  distribution  in  woodlands  may 
be  thus  accounted  for.  The  smaller  larvae  may  even  be 
occasionally  carried  a  short  distance  on  the  feathers  of  a 
bird.  The  caterpillars  are  also  occasionally  transported 
by  the  wind.  As  they  hang  by  threads  from  the  trees 
they  are  sometimes  swept  off  by  sudden  gusts  of  wind  and 
carried  to  a  distance  of  perhaps  a  hundred  yards.  As  the 
moths  are  found  distributed  along  running  streams,  it  is 
probable  that  caterpillars  and  imagoes  are  occasionally  swept 
down  stream,  and  that  now  and  then  an  egg-cluster  is  car- 
ried away  on  a  floating  piece  of  bark  or  dead  twig  or  branch. 
Pieces  of  driftwood  with  eggs  upon  them  have  been  found 
on  the  banks  of  streams  and  on  the  shores  of  islands  in 
ponds.  Egg-clusters  thus  exposed  to  the  action  of  water 
have  been  known  to  hatch.  The  moth  has  been  distributed 
in  the  same  way  along  tide-water  streams  and  even  to  trees 
and  bushes  growing  on  spots  above  the  level  of  tide-water 
in  salt  marsh.  Wherever  the  insect  is  numerous  the  eggs 
are  sometimes  laid  on  the  leaves  of  the  trees.  They  are  fre- 
quently laid  on  dead  leaves  on  the  ground.  In  either  case 
the  leaves  may  be  afterwards  blown  to  some  distance  by  the 
autumnal  winds.  Egg-clusters  may  be  broken  during  gales 
by  the  branches  of  a  tree  beating  against  each  other  or  the 
trunk,  and  the  scattered  eggs  will  then  be  blown  away  by 
the  wind.  Other  ways  in  which  distribution  might  happen 
will  occur  to  those  familiar  with  the  subject.  But  the  pe- 
culiar distribution  of  the  moth  over  a  region  more  than  two 
hundred  square  miles  in  extent  cannot  be  accounted  for 
either  by  the  movements  of  the  caterpillars  or  by  any  of  the 
foregoing  causes,  for  there  are  'well-marked  isolated  colonies 


CAUSES  AFFECTING  DISTRIBUTION.          99 

at  a  distance  of  a  mile  or  more  from  other  infested  localities. 
When  the  action  of  the  regulative  influences  which  at  first 
checked  the  increase  of  the  moth  and  the  limitation  of  its 
powers  of  locomotion  are  considered,  it  seems  improbable 
that  the  moths  could  have  spread  over  thirty  townships  in 
less  than  twenty  years  unless  transported  by  some  human 
agency. 

THE  CONNECTION  or  DISTRIBUTION  AND  POPULATION. 

The  study  of  the  infested  territory  made  in  1891  showed 
that  the  most  densely  infested  areas  were  very  nearly  coin- 
cident with  the  centres  of  population.  In  other  words,  the 
moth  colonies  were  larger  and  more  numerous  in  or  near 
thickly  populated  districts.  (See  map  IV.)  It  was  noted 
that  as  the  inspection  receded  from  Medford,  where  the  moth 
was  first  introduced,  the  towns  were  less  and  less  infested. 
When,  in  this  inspection,  the  centre  of  a  town  next  adjoin- 
ing Medford  was  reached  many  moths  were  found.  As  the 
centre  was  passed  they  grew  less  numerous  until  few,  if  any, 
appeared  along  the  highways.  Such  trees  as  were  found 
infested  were  generally  near  farm-houses  and  other  resi- 
dences. On  approaching  the  next  town  the  moths  were 
again  found  in  considerable  numbers,  although  not  as  nu- 
merously as  in  the  first  town.  After  the  second  town  was 
passed  none  were  found  upon  the  country  roads  leading 
farther  out.  This  led  to  the  hope  that  there  were  no 
moths  in  the  region  beyond.  But  an  inspection  of  the  next 
town  revealed  a  few,  while  in  the  towns  beyond  none  were 
found. 

Outside  of  Medford  the  moths  were  most  numerous  in 
portions  of  the  cities  lying  nearest  to  that  town,  such  as 
Maiden,  Chelsea,  Somerville  and  Cambridge.  Next,  the 
larger  towns,  as  Melrose,  Arlington,  Belmont  and  Win- 
chester, and  the  more  distant  cities,  Lynn  and  Salem,  were 
most  infested.  Comparatively  few  moths  were  found  in  the 
more  sparsely  settled  towns,  like  Lynnfield,  Reading  and 
Lexington.  This  distribution  of  the  moth  along  the  roads 
and  over  populated  districts  led  to  the  assumption  that 
man  was  accountable  for  its  diffusion  as  well  as  its  intro- 
duction. 


100  THE  GYPSY   MOTH. 


THE  DISTRIBUTION  OF  THE  MOTH  BY  MAN'S  AGENCY. 

The  distribution  of  the  moth  by  man,  and  the  means  by 
which  it  was  accomplished,  will  be  better  understood  if  a 
description  of  the  territory  comprised  by  the  infested  towns 
and  cities  is  first  given. 

This  region  extends  along  the  coast  of  Massachusetts  Bay 
from  Boston  harbor  to  the  Beverly  shore.  North  of  Boston 
a  considerable  portion  of  the  land  surface  next  to  the  shore 
consists  of  salt  marsh,  penetrated  here  and  there  by  tidal 
streams  like  the  Mystic  and  Saugus  rivers.  Nahant  and 
Marblehead  Neck  are  bold,  rocky  peninsulas  extending  out 
into  the  sea.  The  Salem  "  Great  pastures,"  lying  not  far 
from  the  sea,  consist  of  rolling  pasture  land  covered  to  some 
extent  with  a  scrubby  growth  of  red  cedars  and  the  charac- 
teristic barberry  and  other  wild  shrubs  of  the  locality.. 

A  long  beach  extends  along  the  outer  border  of  the  salt 
marsh  from  the  Saugus  River  to  the  shores  of  Beachmont, 
and  is  known  locally  as  Crescent  or  Revere  Beach.  It  is  a 
popular  summer  resort.  High  bluffs  front  the  sea  on  the 
Winthrop  peninsula,  and  beyond  them  to  the  south  is  a 
strip  of  gravelly  shore  called  Winthrop  Beach.  A  tide  of 
summer  travel  ebbs  and  flows  along  all  these  shores. 

Back  from  the  shore  in  the  valley  of  the  Mystic  River  an 
open  and  quite  level  country  extends  from  the  salt  marsh 
through  Medford  and  Arlington  to  the  Mystic  lakes,  where 
the  river  has  its  source.  The  Charles  River  valley  through 
Cambridge,  Watertown  and  Waltham  consists  of  a  beautiful 
open  country.  A  range  of  rocky  hills  traverses  the  north- 
central  portion  of  the  infested  district  and  extending  northerly 
and  easterly  from  Lexington  reaches  the  sea  at  Marblehead. 
At  the  Marblehead  shore  these  hills  are  almost  treeless,  but 
in  Swampscott  and  through  Lynn,  Saugus,  Melrose,  Maiden, 
Medford,  Stoneham,  Winchester,  Arlington  and  Lexington 
they  are  more  or  less  clothed  with  trees.  This  rocky,  wooded 
region  is  of  no  great  agricultural  value.  Portions  of  it  have 
been  reserved  for  public  parks  by  the  towns  and  municipali-. 
ties.  A  large  tract  situated  in  Maiden,  Medford,  Winchester 
and  Stoneham  has  been  taken  by  the  State  as  a  public  forest 
reservation.  This  region,  which  is  known  as  the  Middle- 


DISTRIBUTION  BY   MAN.  101 

sex  Fells,  contains  some  of  the  finest  natural  scenery  in  the 
eastern  part  of  the  State.  These  rocky  hills,  crowned 
with  a  growth  of  pines,  cedars,  oaks  and  other  characteristic 
trees,  intersected  by  running  streams  with  here  and  there 
miniature  cascades  and  occasional  reedy  fens,  together  form 
a  succession  of  delightfully  picturesque  scenes  of  rugged 
beauty.  Woodlands  interspersed  with  open  spaces,  fresh- 
water meadows,  towns,  villages  and  farming  lands  extend  to 
the  northern  and  western  boundaries  of  the  infested  region. 
Nearly  all  of  the  southern  portion  of  this  region  is  occupied 
by  Boston  and  its  adjacent  cities. 

The  situation  of  the  towns  and  cities  of  the  infested 
region,  and  their  relative  positions,  may  be  seen  by  reference 
to  the  map.  A  large  proportion  of  the  population  of  Mas- 
sachusetts is  contained  within  this  district.*  Boston  and 
the  cities  in  its  immediate  vicinity  lie  in  or  near  the  Charles 
and  Mystic  valleys.  It  will  be  seen  that  Somerville,  Cam- 
bridge, Chelsea,  Maiden,  Medford,  Everett  and  Waltham 
are  all  cities  lying  in  the  immediate  neighborhood  of  Boston. 
Along  the  shore  to  the  north-east  are  Lynn,  Salem  and  Bev- 
erly. Woburn  is  the  only  city  in  the  north-western  part  of 
the  district. 

The  following  cities  and  towns  are  comprised  within  the 
territory  which  is  or  has  been  infested :  Arlington,  Belmont, 
Beverly,  Boston,  Burlington,  Cambridge,  Chelsea,  Danvers, 
Everett,  Lexington,  Lynn,  Lynnfield,  Maiden,  Marblehead, 
Medford,  Melrose,  Nahant,  Peabody,  Reading,  Revere,  Sa- 
lem, Saugus,  Somerville,  Stoneham,  Swampscott,  Wakefield, 
Waltham,  Watertown,  Winchester,  Winthrop  and  Woburn. 

The  larger  portion  of  the  region  infested  by  the  gypsy 
moth  lies  north  of  Boston.  Boston's  avenues  of  communica- 
tion to  the  north  and  east  and  in  part  to  the  west  run  through 
it.  The  main  lines  of  the  eastern  and  western  divisions  of 
the  Boston  &  Maine  Railroad  pass  through  the  infested 
district  but  east  of  its  centre.  Several  branch  lines  lead  to 
or  through  different  parts  of  the  district.  Two  lines  run 
from  Boston  to  Medford, — the  Medford  branch,  ending  in 


*  By  the  State  census  taken  in  1895  (first  count)  the  population  of  the  cities  and 
towns  of  the  district  infested  by  the  gypsy  moth  is  963,159. 


102  THE   GYPSY  MOTH. 

the  centre  of  the  town,  and  the  main  line  of  the  southern 
division  of  the  Boston  &  Maine  Railroad,  passing  through 
Somerville  and  West  Medford.  The  old  turnpike  roads  from 
Boston  to  Salem,  Newburyport,  Lawrence  and  Lowell  all 
pass  through  the  infested  region.  The  roads  which  pass 
through  this  region  from  Boston  lead  outward  toward  the 
north,  north-east  and  west. 

The  continual  and  immense  traffic  between  Boston  and 
towns  to  the  northward,  coming  and  going  through  the  badly 
infested  region,  together  with  that  in  and  out  of  the  region 
itself,  has  resulted  in  spreading  the  moth  to  many  of  these 
outer  towns.  This  has  been  brought  about  chiefly  by  means 
of  the  transportation  of  caterpillars  on  vehicles.  In  the 
spring  of  1889,  and  in  other  years  when  the  moths  were  in 
greatest  abundance  in  Maiden  and  Medford,  the  young 
caterpillars,  when  disturbed  by  wind  or  by  any  object  strik- 
ing the  branches,  hung  in  great  numbers  by  their  silken 
threads  from  the  trees  in  a  manner  similar  to  that  habitual 
with  the  common  canker  worms.  While  suspended  in  this 
way  above  the  street  they  were  often  struck  by  passing 
vehicles  upon  which  they  dropped,  remaining  either  until  a 
stopping  place  was  reached  or  until  shaken  off  along  the 
roadside.*  Regular  teaming,  daily  or  at  stated  intervals  to 
or  from  a  badly  infested  spot  during  the  time  when  the 
caterpillars  were  very  numerous  on  wayside  trees,  would 
finally  result  in  transporting  numbers  of  them  to  certain 
localities  where  the  wagons  stopped.  A  market  gardener's 
wagon  going  regularly  through  the  infested  region  to  Boston 
and  return,  and  passing  under  infested  trees  along  the  way, 
would  be  very  likely  to  carry  caterpillars  into  the  yard  at  the 
end  of  the  route.  If  a  single  pair  of  the  caterpillars  thus 
transported  survived  and  passed  through  their  transforma- 
tions, and  the  resulting  pair  of  moths  mated,  the  seed  for  a 
colony  might  be  planted.  Even  if  one  female  caterpillar 
survived  and  transformed  into  a  moth,  and  there  Mrere  a  simi- 
larly surviving  male  moth  in  the  neighborhood,  under  favor- 
able conditions  the  latter  might  be  attracted  to  the  former 


•  All  forms  of  the  moth  have  been  found  on  wagons  standing  under  trees.    The 
caterpillars  frequently  crawl  for  shelter  under  the  bodies  of  standing  vehicles. 


DISTRIBUTION   BY   MAN.  103 

and  fertile  eggs  result.  There  were  many  ways  in  which 
the  regular  traffic  with  towns  round  about  was  kept  up  to  or 
through  the  infested  region.  Florists  and  nurserymen  were 
.constantly  sending  plants  to  all  parts  of  the  region  and  to 
Boston.  Truck  farmers'  teams  hauled  loads  of  produce  to 
Boston  and  returned  with  loads  of  manure.  Expressmen 
made  their  regular  trips ;  butchers,  bakers,  peddlers  and 
milkmen  daily  went  their  rounds,  and  the  premises  of  many 
of  these  people  who  were  constantly  driving  about  the 
infested  region  or  through  it  became  infested.  During  the 
summer  there  was  much  carriage  driving  through  the  in- 
fested district,  especially  along  the  North  Shore,  and  this 
also  served  to  distribute  the  moth  to  some  extent.  In  addi- 
tion to  the  transportation  of  the  moth  in  its  various  forms  by 
means  of  vehicles  there  were  other  means  of  distribution 
more  strictly  local.  The  caterpillars  were  carried  about  to 
some  extent  on  the  clothing  of  pedestrians  and  on  the  backs 
of  cattle,  goats,  dogs  and  other  animals. 

While  the  spread  of  the  moth  has  been  mainly  due  to  the 
transportation  of  the  caterpillars,  the  eggs  of  the  creature 
were  also  carried  about  in  various  ways.  Wood  was  cut 
from  infested  trees  and  carried  with  eggs  upon  it  from  one 
town  to  another.  Packing  cases  and  barrels  left  under  in- 
fested trees  are  sometimes  selected  by  the  female  moth  as 
receptacles  in  which  to  deposit  her  eggs.  Barrels  and  cases 
which  had  been  exposed  to  such  infestation  were  not  only 
shipped  about  through  the  infested  region  but  were  some- 
times sent  to  a  considerable  distance  outside.  If  an  egg- 
cluster  laid  on  an  article  thus  shipped  escaped  destruction  en 
route,  there  would  be  danger  of  the  seed  of  a  new  colony 
being  planted  at  the  article's  place  of  destination. 

Instances  of  .Distribution  by  Man. 

It  was  learned  in  1891  that  the  area  occupied  by  the  moth 
was  practically  included  within  the  boundaries  of  thirty  town- 
ships. Since  that  time  it  has  been  found  outside  of  this 
boundary  in  a  few  isolated  cases  only,  each  of  which  was 
accounted  for  by  the  existence  of  driving  or  teaming  from 
the  infested  district.  The  moth  had  reached  these  places 
during  the  few  years  previous  to  1891,  when  it  was  most 


104  THE   GYPSY  MOTH. 

abundant  in  Medford.  These  years  of  its  greatest  abundance 
were  also  the  years  of  its  greatest  diffusion,  for  during  the 
period  when  it  was  most  numerous  on  trees,  about  buildings 
and  along  highways,  many  more  caterpillars  were  carried  out 
on  vehicles  from  the  worst  infested  localities  than  at  any  time 
before  or  since.  From  the  small  size  and  general  appear- 
ance of  most  of  the  colonies  found  in  1891  at  a  distance  from 
Medford,  it  was  apparent  that  they  had  originated  but  two 
or  three  seasons  previous  to  that  time.  On  further  inspec- 
tion it  became  evident  that  the  moth  had  become  widely 
distributed  in  1888,  1889  and  1890  over  the  region  occu- 
pied by  it  in  1891. 

Most  of  this  diffusion  to  a  distance  from  Maiden  and 
Medford  was  accounted  for  by  teaming  and  driving  to  and 
from  the  district  originally  infested.  Therefore,  it  may  be 
termed  the  primary  distribution,  as  it  was  caused  by  trans- 
portation direct  from  the  towns  first  infested.  Here  and 
there,  however,  large  colonies  were  found  that  must  have 
been  growing  for  eight  or  ten  years.  These  colonies,  if  on 
or  near  highways,  had  already  become  centres  of  infestation 
from  which  the  moths  had  been  distributed  widely,  not  only 
along  the  roads  leading  out  of  the  infested  locality  but  also 
back  toward  the  originally  infested  centre  by  means  of 
vehicles  bound  toward  Boston.  This  spreading  from  these 
colonies  may  be  called  a  secondary  diffusion.  Of  this  there 
are  some  interesting  examples.  From  the  large  colony 
in  Swampscott  (see  page  58)  the  moths  were  not  only  dis- 
tributed on  to  Marblehead  but  they  were  also  taken  back 
into  Lynn.  The  Lynn  residence  of  the  owner  of  the  place 
where  the  Swampscott  colony  was  situated  w^as  found  in  1892 
to  have  been  recently  infested,  and  it  was  learned  that  the 
owner  had  been  accustomed  to  drive  frequently  to  the 
Swampscott  place  and  leave  his  horse  and  buggy  in  the  yard 
under  the  infested  trees. 

Early  in  1891  a  colony  was  found  in  North  Cambridge  in 
the  yard  of  Muller  Brothers'  tannery.  As  thirty-five  thousand 
egg-clusters  were  taken  there  the  colony  must  have  originated 
several  years  previous  to  1891.  Dead  horses  were  frequently 
carted  from  Maiden  and  Medford  to  the  Muller  place,  where 
there  were  at  that  time  facilities  for  making  such  use  of  these 


DISTRIBUTION  BY  MAN.  105 

remains  as  was  compatible  with  their  character,  age  and 
general  utility.  It  is  probable  that  the  moths  were  originally 
carried  there  on  the  wagons  which  were  used  for  this  dolo- 
rous traffic.  The  Cambridge  almshouse  was  situated  a  few 
rods  in  the  rear  of  the  tannery.  The  city  swill  was  hauled 
from  all  parts  of  Cambridge  to  this  almshouse  and  was  then 
distributed  for  miles  around  to  farmers  and  others  who  kept 
hogs.  These  swill-takers'  wagons  in  going  and  coming  were 
obliged  to  pass  under  the  branches  of  some  badly  infested 
trees  that  overhang  the  street.  A  tide-water  stream  ran 
through  the  tannery  yard.  An  inspection  revealed  that  the 
trees  along  the  stream  for  many  rods  were  infested.  Here 
was  a  secondary  centre  of  distribution  of  the  first  magnitude. 
Persistent  efforts  were  made  to  stamp  out  this  colony.  When 
this  had  been  done  the  locality  was  carefully  watched.  As 
the  country  roundabout  was  inspected  the  moths  were  found 
scattered  all  over  neighboring  portions  of  Cambridge,  Somer- 
ville  and  Arlington.  In  1893  a  list  of  the  persons  to  whose 
places  swill  had  been  teamed  was  secured  from  Capt.  M.  L. 
Eldridge,  superintendent  of  the  almshouse.  This  comprised 
the  names  of  nearly  three  hundred  people  residing  in  the 
following  towns:  Arlington,  Bedford,  Belmont,  Brighton, 
Burlington,  Cambridge,  Carlisle,  Concord,  Lexington,  Lin- 
coln, Medford,  Somerville,  Waltham,  Watertown,  Weston, 
Winchester  and  Woburn.  The  places  of  more  than  fifty 
people  in  the  list  have  since  been  found  to  be  infested.  The 
results  of  the  investigation  did  not  indicate  that  in  all  cases 
they  had  become  infested  by  the  carriage  of  swill,  for  it  was 
seen  that  some  places  to  which  swill  had  been  hauled  during 
the  months  when  the  caterpillars  were  numerous  upon  trees 
were  not  infested,  while  others  to  which  swill  had  been  hauled 
in  the  winter  only  were  infested.  Yet  it  seems  probable  from 
all  the  data  obtained  from  inquiry  in  these  localities  that 
more  than  half  the  infested  places  had  received  infestation 
from  the  hauling  of  swill  from  the  almshouse. 

Localities  in  the  infested  district  that  are  much  visited  on 
account  of  their  historical  associations  are  usually  found  in- 
fested, and  if  cleared  of  the  moth  are  likely  to  become  re- 
infested.  Many  eminent  men  have  been  buried  in  Mount 
Auburn  Cemetery,  which  lies  partly  in  Cambridge  and  partly 


106  THE   GYPSY   MOTH. 

in  Water-town.  This  cemetery  is  often  thronged  with  visitors 
from  far  and  near.  It  was  well  cleared  of  the  moths  in  1892 
and  1893,  but  in  1895  the  caterpillars  appeared  again  in 
such  quantities  near  the  graves  of  the  poets  Lowell  and 
Longfellow  that  much  effort  was  required  on  the  part  of  the 
workmen  employed  by  the  Board  to  prevent  serious  injury 
to  the  trees  in  the  cemetery.  Though  Charlestown  was 
cleared  of  the  moths  in  the  first  three  years  of  the  work, 
they  were  found  in  1895  at  Monument  Square.  These 
grounds  about  Bunker  Hill  monument  are  much  frequented. 
Many  people  coming  from  other  parts  of  the  infested  region 
have  visited  the  monument  within  a  year.  The  carnival  in 
Charlestown  on  the  17th  of  June,  a  time  when  the  cater- 
pillars are  most  numerous,  draws  thousan4s  of  people  from 
the  region  round  about  to  the  vicinity  of  the  monument. 

A  STUDY  OF   THE   METHODS  AND   ROUTES  or  TRANS- 
PORTATION. 

In  1891  hasty  inspection  of  the  infested  region  finally 
revealed  its  apparent  extent.  This  inspection  was  carried 
on  until,  in  1893,  a  wide  belt  around  the  region  had 
been  examined.  The  question  whether  the  moths  had  been 
transported  to  any  distance  beyond  this  belt  in  sufficient 
numbers  to  continue  the  existence  of  the  species  and  thus 
form  other  centres  of  distribution  remained  unsolved.  It 
was  not  possible  under  the  appropriations  made  to  extend 
the  search  over  the  entire  Commonwealth.  As  it  was  evi- 
dent that  the  moth  was  distributed  principally  by  man,  a 
study  was  made  first  of  the  nature  and  direction  of  the 
traffic  and  travel  which  had  caused  the  dissemination  of  the 
moth  through  the  region  known  to  be  infested ;  next  a  study 
was  made  of  such  similar  traffic  as  extended  to  a  distance 
from  the  infested  region  and  which,  therefore,  might  expose 
other  localities  to  infestation. 

In  studying  methods  of  transportation  special  attention  was 
paid  to  the  steady  and  constant  traffic  back  and  forth  between 
points  within  and  without  the  heart  of  the  infested  district. 
Information  was  also  secured  as  to  the  character,  routes  and 
destination  of  outward  freight  shipments  by  road  and  rail, 
and  of  the  vast  miscellaneous  traffic  and  pleasure  driving 


DISTRIBUTION  BY  MAN.  107 

over  the  road.  Inquiries  were  first  made  in  the  inner  and 
worst  infested  towns.  Supplementary  and  additional  infor- 
mation was  gathered  later  outside  the  infested  district  in  those 
localities  known  to  have  had  more  or  less  communication  with 
the  "  danger  tract"  of  the  infested  region  during  the  greatest 
prevalence  of  the  moth.  This  ' '  danger  tract"  was  the  heart  of 
the  infested  region  (Medford  and  Maiden)  because  the  swarm- 
ing numbers  of  the  caterpillars  there  had  made  possible  their 
frequent  transportation  by  vehicles  to  other  points.  At  first 
there  was  not  so  much  danger  of  such  transportation  from 
anywhere  else  in  the  infested  district  because  of  the  com- 
parative scarcity  of  the  moths  in  other  localities  and  the 
usual  small  size  of  their  colonies.  This  study  shed  a  flood 
of  light  upon  the  manner  of  the  distribution  of  the  moths  in 
the  territory  originally  infested  from  Medford,  and  explained 
the  existence  of  many  colonies  in  woods  and  other  retired 
places.  It  also  indicated  the  places  which  had  been  most 
exposed  to  infestation  in  the  territory  lying  beyond  the 
known  limits  of  the  moth's  spread. 

The  investigation  of  the  transportation  of  the  moth  was 
confined  mainly  to  the  traffic  and  communication  to  the  north, 
east  and  west  of  Medford.  The  great  bulk  of  all  driving  over 
the  road  and  the  still  greater  proportion  of  ' '  dangerous  "  or 
constant  traffic  was  to  the  north  and  west  and  along  the 
North  Shore  to  the  north-east,  and  consequently  the  moth 
had  been  diffused  farther  in  those  directions.  There  is  little 
constant  and  direct  teaming  traffic  to  any  other  southern 
point  than  Boston,  and  the  latter  place,  by  reason  of  the 
small  number  of  trees  in  its  business  sections,  was  a  com- 
paratively safe  point  for  the  reception  of  such  traffic. 

In  the  inquiry  in  regard  to  the  traffic  over  the  road,  all 
information  possible  was  obtained  concerning  the  routes  of 
expressmen  and  movers,  market-gardeners,  farmers,  milk, 
hay  and  wood  dealers,  swill-takers,  butchers,  peddlers  and 
junk  men.  Local  boards  of  health  and  milk  inspectors  in 
and  around  Boston  furnished  information  by  means  of  which 
those  engaged  in  the  milk  business  and  in  swill  taking  were 
located  and  their  routes  ascertained.  Much  information  was 
secured  in  regard  to  the  great  market-gardeners'  traffic  over 
the  road  between  Boston  and  towns  within  the  infested  district 


108  THE  GYPSY  MOTH. 

or  to  the  north,  and  west  of  it.  Information  was  sought  in 
regard  to  excursions  and  picnics  to  the  groves  situated  on  all 
sides  of  the  worst  infested  district.  Much  knowledge  was 
obtained  in  regard  to  the  grounds  used  by  church  and  Sunday 
school  picnic  parties  from  Maiden,  Medford,  Revere,  Somer- 
ville,  Cambridge,  Arlington,  Melrose,  Lynn  and  Everett. 
Places  of  great  public  resort,  like  militia  and  camp-meeting 
grounds,  were  also  noted  and  were  later  examined.  Facts 
bearing  upon  the  hauling  of  wood  to  or  through  the  infested 
district  were  carefully  gathered.  Inquiries  were  made  of 
expressmen  and  movers  in  regard  to  the  destination  of  families 
which  had  moved  from  badly  infested  localities,  and  as  to 
the  large  amount  of  summer  moving  and  teaming  along  the 
North  Shore,  and  the  amount  of  teaming  over  the  road  weekly, 
monthly  or  yearly  between  the  infested  district  and  centres 
of  traffic  like  Lawrence  and  Lowell.  The  matters  of  ship- 
ments of  nursery  stock  and  greenhouse  plants  over  the  road 
and  of  towns  visited  and  routes  taken  by  peddlers  and  junk 
dealers  were  also  investigated.  A  vast  amount  of  facts 
bearing  on  the  subject  of  miscellaneous  driving  was  also 
obtained.  The  inquiry  was  not  entirely  confined  to  the 
heart  of  the  infested  district  but  was  extended  to  less  infested 
places  like  Lynn  and  Salem.  The  scope  of  the  whole  in- 
vestigation quickly  broadened.  Clues  obtained  within  the 
infested  district  were  followed  out,  and  this  led  to  much 
additional  inquiry  in  many  towns  to  the  north-east,  north 
and  west  of  the  infested  region.  Every  possible  fact  and 
item  bearing  upon  the  subject  of  communication  with  the 
moth-region  were  obtained.  It  was  not  difficult  in  country 
towns  to  learn  who  were  the  regular  and  who  the  occasional 
visitors  to  or  from  the  infested  district  and  what  was  th$ 
nature  of  their  business.  The  lines  of  travel  were  also  easily 
learned.  In  cities  like  Lawrence  and  Lowell  which,  although 
farther  away,  were  in  a  sense  exposed  because  of  their  being 
centres  of  population,  lists  were  obtained  of  teamsters  and 
movers  who  went  more  or  less  frequently  to  the  district  to 
the  south  and  the  character  of  their  business  was  learned. 
These  local  teamsters  as  a  rule  made  their  return  trips  empty 
handed,  and  thus  the  danger  of  moth  transportation,  except 
by  the  vehicle  itself,  was  avoided. 


DISTRIBUTION  BY  MAN.  109 

The  investigation  and  the  subsequent  inspection  based 
thereon  revealed  the  important  fact  that  the  most  dangerous 
traffic  was  that  going  only  a  short  distance  from  the  centre 
of  the  infested  district.  A  large  proportion  of  this  did 
not  even  go  out  of  the  district,  and  nearly  all  the  re- 
mainder went  but  little  farther.  The  proof  of  this  is  ample. 
The  most  dangerous  traffic  is  the  steady  and  constant  traffic 
back  and  forth  between  the  same  points  which,  by  its  regu- 
larity, makes  possible  the  occasional  transportation  of  cater- 
pillars to  the  same  locality.  This  regular  traffic  includes  the 
trips  of  market-gardeners,  farmers,  milkmen,  swill-takers 
and  others  living  in  the  outer  towns  of  the  infested  district 
or  in  the  towns  next  beyond,  who  go  daily  or  weekly  in  and 
out  of  the  heart  of  the  infested  district  or  through  it  to 
Boston  and  return.  Nearly  all  of  the  foregoing  classes  of 
people  live  comparatively  near  the  heart  of  the  infested  dis- 
trict. None  of  them  live  very  far  away.  In  a  word,  in 
proportion  as  the  distance  from  the  heart  of  the  infested  dis- 
trict increased,  the  regularity  and  frequency  of  traffic  to  and 
fro  decreased,  and  in  the  same  ratio  the  danger  of  moth 
transportations  and  consequent  possible  establishment  of  new 
colonies  diminished.  The  work  of  four  years  has  proved 
that  new  colonies  at  a  distance  from  the  infested  centre 
have  owed  their  origin  and  rise,  not  to  a  single  transportation 
of  the  moth  but  to  various  cases  of  the  sort  which  have 
been  made  possible  by  steady  communication  over  the  road 
between  two  points.  Even  pleasure  driving,  when  con- 
stant and  frequent  between  an  infested  locality  and  one  out- 
side, has  been  responsible  for  the  establishment  of  a  new 
colony. 

In  the  study  of  traffic  and  driving  of  all  sorts  over  the 
road,  the  question  of  routes  became  of  the  utmost  impor- 
tance. The  vast  aggregate  amount  of  wheeling  by  its  very 
existence  caused  the  roadsides  of  all  main  highways  and  the 
neighborhoods  of  hotels,  village  stores,  blacksmith  shops 
and  watering  troughs  to  become  more  or  less  exposed,  the 
danger,  of  course,  decreasing  as  the  distance  increased  from 
the  infested  district.  There  were  two  reasons  for  this: 
first,  the  great  bulk  of  all  wheeling,  miscellaneous  as  well 
as  regular,  did  not  go  to  a  great  distance ;  second,  the  ma- 


110  THE  GYPSY  MOTH. 

jority  of  larvae  transported  on  vehicles  are  undoubtedly  shaken 
or  brushed  off  before  many  miles  are  traversed. 

The  possible  danger  attaching  to  freight  shipments  by  rail 
from  Maiden  and  Medford  was  investigated  by  an  examina- 
tion of  "freight  forwarded"  books  at  the  various  stations. 
The  examination  of  these  books  revealed  the  origin,  character 
and  destination  of  shipments  since  1880.  The  origin  and 
character  of  shipments  immediately  revealed  the  danger,  if 
any,  attaching  to  them.  To  illustrate :  Manufactures  and 
household  goods,  constituting  the  bulk  of  shipments,  com- 
ing as  they  do  from  in-doors,  are  practically  safe  shipments  ; 
while  articles  which  have  been  exposed  out  of  doors,  such  as 
empty  boxes,  nursery  stock,  bricks,  stones,  scrap  iron  or 
builders'  materials,  may,  if  coming  from  an  infested  locality, 
be  dangerous  shipments.  In  this  connection  the  matter  of 
date  of  shipment  was  important.  Some  articles,  by  reason 
of  their  place  of  origin,  might  be  dangerous  shipments  only 
during  the  larval  season ;  others,  only  during  the  months 
when  the  eggs  are  the  only  living  form  of  the  moth.  Fi- 
nally, the  examination  of  the  freight  books  revealed  the 
receivers  of  goods  (whether  in  or  out  of  the  infested  district) . 

The  danger  of  moth  transportation  on  freight  sent  by  rail 
was  shown  by  the  investigation  to  be  very  slight.  The 
proportion  of  shipments  which  on  account  of  their  character 
or  frequency  might  be  considered  as  dangerous  was  extremely 
small.  *  The  destination  of  these  being  known,  it  was  possible 
to  do  supplementary  work  in  the  nature  of  inquiry  and 
inspection  at  these  points  of  destination.  In  most  cases  such 
work  was  done. 

The  matter  of  shipments  of  bricks  from  Medford  deserves 
special  mention  in  this  connection  both  because  of  its  intrinsic 
importance  and  as  an  illustration  of  the  methods  of  inquiry 
pursued.  The  premises  of  the  Anderson  Pressed  Brick 
Company  were  in  the  past  badly  infested.  Shipments  of 
brick  had  been  made  to  many  points  outside  the  infested 
territory.  Most  cases  were  investigated  and  an  inspection 
made  at  the  places  to  which  the  brick  had  been  shipped.  In 
this  work  the  agents  of  the  Board  visited  a  number  of  towns 

•  This  is  equally  true  of  freight  shipments  over  the  highway. 


DISTRIBUTION   BY   MAN.  Ill 

widely  scattered  over  the  State.  Although  the  danger  of 
the  transportation  of  the  moth  in  the  egg  form  had  appeared 
serious,  no  trace  of  the  insect  was  anywhere  found.* 

In  addition  to  the  freight  shipments,  another  danger  of 
moth  transportation  lay  in  the  possibility  of  the  cars  them- 
selves carrying  some  form  of  the  moth.  This  might  happen 
in  case  a  car  had  stood  for  some  time  on  a  siding  near  infested 
trees  or  other  objects.  Two  instances  are  recorded  where 
egg-clusters  have  been  found  on  freight  cars  standing  on 
sidings.  This  led  to  an  inquiry  into  the  condition  of  rail- 
road sidings,  whether  treeless  or  not,  and  if  the  latter, 
whether  infested  or  not.  It  was  obvious  that  if  moths  were 
transported  by  cars  and  new  colonies  started,  these  would 
be  found  along  the  lines  of  railroad,  probably  at  sidings  and 
stations.  This  later  led  to  the  inspection,  as  a  measure  of 
precaution,  of  the  lines  of  railroad  running  north  and  west 
out  of  the  infested  district,  the  eastern  and  western  divisions 
of  the  Boston  &  Maine  road  being  followed  out  as  far  as 
Portland,  Me.,  the  southern  division  as  far  as  Concord,N.  H., 
and  the  Fitchburg  road  as  far  as  Fitchburg.  In  the  matter  of 
possible  danger  of  moth  transportation  by  cars,  the  shipment 
of  wood  to  the  Bay  State  Brick  Company  in  Medford  de- 
serves mention.  The  premises  of  this  brick  company  are 
infested.  Thousands  of  cords  of  wood  are  shipped  there 
yearly  from  New  Hampshire  points,  and  the  same  platform 
cars  were  in  the  past  often  sent  back  and  forth  again  and 
again.  A  certain  amount  of  danger  had  unquestionably 
attached  to  this  species  of  traffic.  The  places  of  shipment 
in  New  Hampshire  were  consequently  visited  and  the  sidings 
in  their  neighborhood  carefully  examined,  but  no  trace  of  the 
moth  was  found.  In  this  work  additional  information  was 
secured  whenever  possible  as  to  any  communication  between 
outside  points  and  the  infested  region.  This  inspection  of 
suspected  localities  outside  the  State  was  rendered  necessary 
in  connection  with  the  policy  of  extermination,  which  pro- 
ceeded on  the  theory  that  the  moth  was  confined  to  a  limited 
area  in  the  State  of  Massachusetts. 


*  The  danger  of  transportation  of  eggs  was  lessened  by  the  fact  that  the  finest 
bricks,  the  only  ones  sent  to  a  distance,  were  cleaned  before  being  shipped. 


112  THE   GYPSY  MOTH. 

At  the  height  of  the  caterpillar  plague  in  Medford,  it  is 
said  that  it  was  almost  impossible  for  people  going  through 
the  streets  leading  to  the  Glenwood  station  of  the  Medford 
branch  railroad  to  avoid  carrying  caterpillars  which  dropped 
down  upon  their  clothing  from  the  wayside  trees.  (See  the 
statement  of  Mr.  Sylvester  Lacy  on  page  17.)  As  the  rail- 
road ran  only  from  Medford  to  Boston,  there  was  not  as 
much  danger  of  the  caterpillars  being  transported  to  a  dis- 
tance by  means  of  the  luggage  and  clothing  of  passengers 
as  there  would  have  been  had  the  railroad  passed  through 
Medford  to  other  parts  of  the  State  or  to  other  States. 
Nevertheless,  during  1888,  1889  and  1890  very  many  cater- 
pillars undoubtedly  were  carried  in  this  way  not  only  to 
Boston  but  to  other  parts  of  the  State.  Even  in  1891  cater- 
pillars were  thus  frequently  carried.  An  agent  of  the  Board 
of  Agriculture  stated  to  the  writer  that  in  1891  he  took  a 
gypsy-moth  caterpillar  from  the  cloak  of  a  lady  standing  in 
front  of  the  ticket  office  in  the  western  division  station  of 
the  Boston  &  Maine  Railroad  in  Boston.  The  lady  had 
come  from  Medford  and  had  just  bought  a  ticket  for  North- 
ampton, a  city  in  the  Connecticut  valley.  Had  the  cater- 
pillar not  been  removed  from  her  cloak,  it  might  have  been 
carried  a  long  distance,  or  if  left  upon  the  cars  it  might  have 
escaped  observation,  dropping  off  eventually  at  some  point 
along  the  road.  If  such  cases  have  frequently  occurred  the 
question  at  once  arises,  why  have  not  moth  colonies  been 
formed  far  and  wide?  While  at  first  sight  it  would  seem 
probable  that  they  have  been  thus  formed,  yet  upon  con- 
sideration it  is  seen  that  the  carriage  of  caterpillars  in  this 
way  to  a  distance  is  not  necessarily  dangerous. "  The  farther 
a  caterpillar  is  carried  from  others  of  its  kind  the  less  be- 
comes the  probability  of  its  reproduction.  The  female  moth 
does  not  fly.  With  favoring  winds  in  open  country  the  male 
can  find  the  female,  by  means  of  his  sensory  organs,  at  a 
distance  of  about  half  a  mile.  The  change  of  cars  which  was 
necessary  in  Boston,  and  the  radiation  of  the  railroads  to  the 
north,  east,  south  and  west,  served  to  decrease  the  chances 
of  propagation,  for  the  farther  a  caterpillar  was  carried  from 
Boston  the  greater  became  the  distance  which  separated  it, 
not  only  from  the  infested  region,  but  from  other  lines  of 


DISTRIBUTION   BY  MAN.  113 

railroad  leading  out  of  Boston  on  which  other  caterpillars 
might  be  carried  out.  Thus,  though  many  caterpillars  might 
be  accidentally  carried  to  a  long  distance  outside  the  infested 
region,  there  was  very  little  probability  that  any  number  of 
such  individuals  would  be  dropped  within  half  a  mile  of  each 
other.  Furthermore,  the  chances  that  isolated  caterpillars 
would  complete  their  transformations  and  emerge  as  perfect 
insects  are  very  small.  Therefore,  there  would  be  hardly  a 
possibility  of  a  colony  being  started  by  the  accidental  trans- 
portation of  caterpillars  to  a  distance  unless  it  should  be 
proved  that  parthenogenesis  (the  reproduction  of  the  species 
by  the  virgin  female)  occurs.*  If,  however,  the  moths  should 
at  any  time  become  abnormally  numerous  on  the  line  of  an 
extended  railway,  their  chances  of  accidental  distribution  by 
regular  and  constant  travel  would  greatly  increase  and  a 
wide  dissemination  would  almost  certainly  follow.  So  far, 
notwithstanding  the  unhindered  carriage  of  caterpillars  in 
this  way  on  the  Medford  branch  railroad  for  several  years 
previous  to  1892,  no  evidence  of  the  moths'  existence  at  a 
distance  from  the  infested  towns  has  ever  been  found  along 
the  lines  of  other  railroads. 

THE  EFFECT  OF  THE  WORK  OF  EXTERMINATION  ON  THE 
DISTRIBUTION  OF  THE  MOTH. 

"While  the  work  of  destroying  the  gypsy  moth  has  much 
reduced  the  numbers  of  the  moths  and  the  extent  of  territory 
occupied  by  them,  it  has  been  necessary  to  exercise  great  care 
to  avoid  accidental  distribution  of  the  caterpillars  by  the 
workmen. 

The  work  of  spraying  is  responsible  for  some  slight  local 
scattering  of  the  caterpillars.  When  the  branches  of  a  tree  are 
disturbed  by  the  sprayers,  many  of  the  caterpillars  spin  down 
and  either  fall  to  the  ground  or  are  carried  about  upon  the 
clothing  of  the  workmen  or  others  passing  beneath  the  tree. 
Unless  great  care  is  taken  they  may  be  carried  from  place  to 
place  on  the  spraying  team.  Those  falling  to  the  ground 

*  Observations  so  far  made  in  this  country  have  not  revealed  a  case  of  partheno- 
genesis in  this  species,  but,  on  the  contrary,  many  instances  have  shown  isolation 
to  result  in  extermination.  A  few  European  instances  of  parthenogenesis  have  been 
recorded. 


114  THE   GYPSY  MOTH. 

frequently  crawl  to  other  trees,  and  if  later  these  trees  are 
sprayed  many  of  the  caterpillars  crawl  still  farther.  It  is 
almost  impossible  to  avoid  scattering  the  moths  when  spray- 
ing is  resorted  to,  which  makes  it  necessary  to  spray  all 
vegetation  near  an  infested  spot,  that  the  scattering  cater- 
pillars may  find  poisoned  food. 

As  the  work  of  burlapping  has  progressed  since  1891  the 
proportion  of  caterpillars  seeking  the  shelter  of  the  burlap 
appears  to  have  diminished.  Many  either  remain  in  the 
tops  of  trees  or  seek  out  places  near  the  ground  in  which 
to  secrete  themselves.  There  also  seems  to  be  a  tendency 
to  scatter  farther  and  farther  from  the  infested  localities. 
These  habits  may  have  been  induced  by  the  frequent  dis- 
turbing of  the  caterpillars  in  the  work  of  burlapping,  or  here 
may  be  another  illustration  of  the  survival  of  the  fittest. 
When  the  caterpillars  are  very  young  and  while  the  workmen 
are  placing  the  burlap  bands  about  the  trees  they  are  likely 
to  dislodge  some  of  the  caterpillars  which,  falling  upon  their 
clothing,  may  be  carried  about  from  place  to  place.  To  lessen 
the  risk  of  such  carriage  the  workmen  in  summer  are  dressed 
in  a  uniform  suit  of  a  light  color  so  that  any  dark  object 
falling  upon  them  may  contrast  strongly  with  their  clothing. 
The  men  are  also  cautioned  to  examine  carefully  each  other's 
clothing  when  leaving  an  infested  place.  Notwithstanding 
this  precaution  it  is  possible  that  a  few  localities  from  which 
the  moths  have  been  entirely  exterminated  have  become  re- 
infested  in  this  way,  for  occasionally  a  place  in  which  no 
form  of  the  moth  has  been  found  for  a  year  or  two  becomes 
again  infested.  In  such  cases  from  one  to  three  or  four 
caterpillars  have  been  found  during  the  season,  not  a  suffi- 
cient number  to  indicate  that  eggs  had  been  laid  there  in  the 
previous  season. 

The  Distribution  Restricted  and  Changed. 
As  far  as  the  work  of  extermination  has  proceeded  it  has 
radically  changed  the  distribution  of  the  moth.  It  is  often 
the  case  that  the  most  persistent  and  thorough  work  will  not 
exterminate  the  moths  from  a  locality  in  one  year.  It  is 
necessary  to  search  a  locality  for  several  years  in  order  to 
be  assured  that  the  moths  are  all  destroyed  and  no  seed  is 


ITS  DISTRIBUTION  CHANGED.  115 

left.  But  we  have  now  sufficient  data  for  the  belief  that  the 
moths  found  in  most  colonies  in  the  outer  towns  in  1891, 
1892  and  1893  have  been  exterminated.  In  this  way  the 
outward  spread  of  the  moth  to  new  territory  has  been 
restricted.  It  has  been  necessary,  as  a  part  of  the  policy  pur- 
sued in  preventing  the  spreading  of  the  moth  towards  towns 
outside  the  boundary  of  the  infested  region,  to  search  carefully 
the  borders  of  highways  and  streets  in  towns  and  cities,  as  it 
was  from  cultivated  grounds  in  populous  towns  and  by  high- 
ways leading  from  the  towns  that  the  moths  were  mostly  dis- 
tributed. As  the  moths  in  the  woods  spread  slowly,  and  were 
less  liable  to  transportation  outside  the  infested  region  than 
those  in  the  residential  and  business  sections,  work  was  con- 
centrated upon  these  districts  to  the  neglect  of  the  woodland. 
As  has  already  been  stated,  the  centres  of  distribution  in  1891 
coincided  with  the  centres  of  population,  and  in  the  attempt  to 
clear  these  centres  and  prevent  injury  to  valuable  trees  and 
plants  the  larger  part  of  each  appropriation  was  used.  From 
what  was  learned  yearly  by  the  woodland  searchers  it  was  be- 
lieved that  the  moths  were  increasing  and  spreading  in  the 
woods.  The  committee  in  charge  of  the  work  stated  this  be- 
lief year  after  year  to  the  legislative  committees  and  strongly 
urged  in  their  reports  to  the  Legislature  that  more  money  be 
appropriated,  for  the  inspection  of  the  woodlands  and  the 
destruction  of  the  moths  within  their  borders.  Sufficient 
appropriations  not  being  forthcoming  the  result  of  the  neg- 
lect of  the  woodland  is  now  shown  in  the  present  distribution 
of  the  moth.  The  normal  ditfusion  from  centres  coinciding 
with  the  centres  of  population  has  given  place  to  a  much 
slower  dissemination  from  centres  situated  in  the  woodlands 
of  the  north-central  infested  towns.  Though  much  work 
has  been  done  in  these  woodlands  it  has  been  from  necessity 
superficial  and  has  merely  resulted  in  partially  holding  the 
moths  in  check.  In  some  localities  where  the  woods  were 
not  searched  the  increase  and  spread  have  been  unimpeded 
because  the  colonies  were  not  known. 

In  the  report  of  the  work  of  the  year  1894,  made  by  the 
Board  of  Agriculture  to  the  Legislature,  it  was  stated  as 
probable  that  the  moths  were  scattered  through  the  woods 
from  Lexington  to  the  sea.  That  this  probability  has  be- 


116  THE  GYPSY  MOTH. 

come  a  certainty  is  shown  by  the  developments  of  the  season 
of  1895.  As  has  before  been  stated,  there  are  in  this  region 
three  centres  of  infestation  of  at  least  a  thousand  acres  each. 
(See  page  87. )  These  centres  are  included  in  a  belt  of  wood- 
land a  mile  in  width,  which  is  all  more  or  less  infested, 
reaching  with  some  interruptions  from  East  Lexington  to 
Salem,  a  distance  of  about  eighteen  miles. 

As  compared  with  1889  the  moths  in  open  and  cultivated 
lands  are  now  much  reduced  in  numbers  in  the  worst  in- 
fested sections  and  are  elsewhere  extinct  or  comparatively 
rare.  On  the  other  hand,  in  the  belt  of  woodland  north  of 
the  centre  of  the  infested  region  they  occupy  more  ground 
than  in  1889,  and  the  number  of  badly  infested  places  is 
greater. 


!i 


. 


5 1 

I! 


THE  DESTRUCTION  OF  THE  EGGS.         117 


METHODS   USED   FOR   DESTROYING    THE 
GYPSY  MOTH. 

THE  DESTRUCTION  OF  THE  EGGS. 

As  the  egg-clusters  of  the  gypsy  moth  are  of  a  conspicuous 
color  and  may  be  found  upon  trees  and  other  objects  during 
at  least  eight  months  of  the  year,  the  possibility  of  stopping 
the  moth's  increase  by  destroying  great  numbers  of  cater- 
pillars in  embryo  becomes  apparent.  In  each  buff  egg-cluster 
temptingly  displayed  upon  the  tree  trunks  during  the  fall, 
winter  and  spring  there  are  from  three  hundred  to  fourteen 
hundred  potential  caterpillars.  Destroy  the  egg-cluster  and 
apparently  you  have  disposed  of  the  coming  brood.  You 
have  prevented  the  hatching  of  the  eggs  and  the  consequent 
spreading  of  the  caterpillars  which  otherwise  would  have 
scattered  abroad,  feeding  upon  nearly  all  kinds  of  trees, 
shrubs  and  garden  plants.  Obviously  it  is  safer,  easier  and 
less  expensive  to  destroy  the  egg-cluster  in  which  the  brood 
is  united  and  stationary  than  to  find  and  destroy  the  cater- 
pillars after  they  have  hatched  and  scattered.  The  destruc- 
tion of  eggs  may  not  always  secure  extermination,  as  the 
female  imago  sometimes  scatters  fertile  eggs  upon  the  ground, 
and  concealed  egg-clusters  may  sometimes  be  overlooked. 
Yet  persistent  and  thorough  egg-destruction  in  the  autumn, 
winter  and  spring  may  be  relied  upon  to  so  reduce  the  num- 
ber of  the  moths  that  they  will  do  comparatively  little  injury 
in  the  ensuing  summer.  Egg-killing  is  recommended  by 
many  European  authors  as  the  first  and  chief  method  of  pre- 
venting the  ravages  of  the  moth. 

Bechstein  wrote  in  1804:  "The  clusters  of  eggs  can  be 
looked  for  from  the  last  of  September  or  October  to  March, 
upon  the  trunks  of  trees,  walls,  hedges  and  fences,  and  may 
be  crushed  or  knocked  off  into  a  pot  and  burned  by  kindling 
a  fire  upon  them."* 

Canon  Schmidberger,  who  wrote  the  papers  on  "Insects 

*  "  Vollstandige  Naturgeschichte  der  schadlichen  Forstinsekten,"  Leipzic,  1804, 

page  372. 


118  THE  GYPSY  MOTH. 

Injurious  to  Fruit  Trees "  for  Vincent  Kollar's  work,  pub- 
lished at  Vienna,  Austria,  says  :  "  With  respect  to  destroy- 
ing these  insects,  the  first  thing  that  is  necessary  is  to  find 
out  the  egg-masses  and  destroy  them."* 

This  method  is  quite  generally  employed  in  European 
countries  where  the  gypsy  moth  is  plentiful.  We  have  con- 
ducted a  considerable  foreign  correspondence  to  determine 
what  methods  are  now  in  use  in  European  countries  to  check 
the  ravages  of  the  moth.  Under  date  of  Aug.  29,  1895, 
Dr.  Antonio  Augusto  Carvalho  Monteiro  writes  from  Lis- 
bon, Portugal:  "We  generally  endeavor  to  kill  the  larvas 
at  about  the  end  of  June,  or  to  destroy  the  cottony  discs 
which  enclose  the  eggs  during  autumn,  by  scraping  the 
trunks  of  the  trees,  the  walls,  etc.,  and  then  crushing  or 
burning  them,  or  sometimes  even  covering  them  with  a 
thick  layer  of  coal  tar  by  means  of  brushes." 

Professor  Henry  of  the  School  of  Forestry  at  Nancy, 
France,  writes  under  date  of  July  27,  1895:  "The  best 
thing  to  do  is  to  kill  the  heavy  female  wherever  it  is  met 
with,  and  especially  to  coat  the  egg-clusters,  generally  very 
easily  seen,  with  a  thick  coat  of  tar  by  means  of  a  brush  at 
the  end  of  a  pole." 

Prof.  N.  Nasonov  writes  from  Warsaw  University  Mu- 
seum of  Zoology  in  Russia,  Aug.  7,  1895,  stating  that  the 
first  method  used  is  scraping  the  bark  from  the  trees  after 
the  deposit  of  the  eggs. 

Prof.  Max.  Fingerling  writes  from  Leipzic,  Germany,  on 
Aug.  9,  1895  :  "  The  best  method  of  holding  the  insects  in 
check  is  by  destroying  their  eggs.  In  this  particular  case 
nature  has  provided  a  means  in  the  easily  recognizable  egg- 
clusters." 

When  in  1891  the  people  of  the  infested  region  were  con- 
sulted by  the  agents  of  the  second  commission  for  the  exter- 
mination of  the  gypsy  moth,  it  was  found  that  there  existed 
among  them  a  strong  prejudice  against  spraying,  and  also  a 
belief  that  it  was  not  effective  with  the  gypsy  moth.  Gather- 
ing the  eggs  was  believed  by  those  who  had  fought  the  moth 
in  Medford  to  be  the  most  effective  method  of  destruction 

*  "  A  Treatise  on  Injurious  Insects,"  by  Vincent  Kollar,  English  translation  by 
J.  and  M.  Loudon,  London,  1840,  page  202. 


BURNING   THE   EGGS.  119 

then  in  use.  Egg-killing  was  begun  by  the  commissioners, 
who,  fearing  that  spraying  might  not  prove  effective,  deter- 
mined to  leave  no  stone  unturned,  but  to  give  all  promising 
methods  a  thorough  trial. 

Burning  the  Eggs. 

Professor  Fernald  had  recommended  in  1889  that  the  eggs 
of  the  moth  be  scraped  from  the  trees  and  burned.  This 
was  the  most  effectual  method  of  egg-killing  pursued  by  the 
first  commission.  During  the  spring  of  1891  it  was  used 
by  the  second  commission  and  later  by  the  employees  of  the 
State  Board  of  Agriculture.  The  eggs  were  scraped  off  or 
cut  away  from  the  objects  upon  which  they  rested,  placed  in 
tin  cans  and  burned  in  stoves  or  brush  fires.  A  fierce  heat 
is  required  to  ensure  their  destruction.  When  exposed  to 
such  heat  they  finally  burst  with  a  snapping  like  a  bunch  of 
miniature  fire-crackers  or  the  cracking  of  corn  in  a  popper. 
Whenever  the  eggs  were  very  numerous  in  undergrowth  or 
waste  land,  fire  was  run  through  the  dead  leaves  and  debris 
as  an  experiment;  but  this  method  seemed  to  have  little 
effect,  as  the  heat  was  not  sufficiently  intense.  The  hairy 
covering  of  the  egg-clusters  seems  to  possess  remarkable 
non-conductive  properties,  rendering  the  eggs  almost  imper- 
vious for  a  time  to  sudden  intense  heat.  Even  with  the 
hottest  fire  that  can  be  applied  to  the  egg-clusters,  some 
minutes  are  required  to  destroy  them  utterly.  A  running 
brush  fire  merely  scorched  the  outside  of  the  cluster,  killing 
perhaps  a  few  of  the  eggs  in  the  external  layer,  but  leaving 
the  majority  uninjured.  Experiments  were  next  made  with 
crude  petroleum,  by  spraying  it  over  the  ground  and  vegeta- 
tion by  means  of  watering  pots  and  then  igniting  it'.  The 
fire  thus  made  was  fierce  enough  to  destroy  the  small  under- 
growth and  the  upper  layer  of  leaves,  together  with  most 
of  the  eggs,  but  such  egg-clusters  as  remained  under  roots 
or  rocks  were  not  injured.  Considerable  oil  was  wasted  by 
soaking  into  the  ground,  and  the  remainder  did  not  give 
the  degree  of  heat  which  is  obtained  by  atomizing.  Experi- 
ments were  then  made  with  a  view  of  perfecting  a  burning 
machine  which  would  incinerate  all  undergrowth  in  a  given 
tract.  The  first  experiments  were  not  entirely  successful, 


120 


THE   GYPSY  MOTH. 


as  the  machines  were  either  too  cumbersome  or  could  not 
be  used  on  rough  or  uneven  ground.  It  was  found  necessary 
to  provide  an  apparatus  which  would  distribute  the  oil  in 
a  spray,  as  when  thus  thrown  in  fine  particles  in  the  air  and 
ignited,  it  formed  an  extremely  hot  gas  flame  and  was  con- 
sumed to  the  best  advantage.  For  economy's  sake  such  an 
apparatus  must  be  light  enough  to  be  carried  and  operated 
by  two  men,  as  wagons  could  not  be  driven  over  much  of 
the  ground  upon  which  this  work  was  done.  Experiments 
were  made  with  the  cyclone  nozzle.  (Plate  XXVH. ,  Fig.  2. ) 
An  oil  spray  from  this  nozzle  when  ignited  was  found  to 
give  a  very  hot  and  effective  flame.  Crude  oil  was  first 

used  as  a  burning 
fluid,  but  as  it  is 
very  objectionable 
on  account  of  its 
rank  odor,  "  paraf- 
fine  gas"  oil  was 
substituted  later. 
This  oil  has  less 
odor  and  burns  to 
better  advantage , 
but  is  somewhat 
more  expensive.  A 
fifteen-gallon  tank 
which  could  be  readily  carried  about  by  two  men  was  pro- 
vided. On  such  a  tank  a  Johnson  pump  with  a  fine  strainer 
placed  over  the  suction  pipe  was  mounted,  and  a  short 
hose  of  the  kind  made  for  the  delivery  of  oil  was  attached. 
Ordinary  rubber  hose  is  worthless  for  such  a  purpose,  as  it 
is  soon  destroyed  by  the  corrosive  action  of  the  oil,  and  in 
the  mean  time  the  disintegrated  particles  frequently  clog  the 
nozzle.*  A  pole,  consisting  of  an  iron  pipe  twelve  feet 
long,  braced  by  being  surrounded  by  wood  for  three-fourths 
of  its  length,  was  coupled  to  the  hose.  (See  Fig.  1.)  No 
solder  could  be  used  in  the  fittings  of  the  pipe  or  nozzle, 


FIG.  1.    The  cyclone  burner. 


*  The  best  "  oil  hose  "  that  can  be  obtained  will  soon  become  corroded,  clogging 
the  nozzle.  If  an  "  automatic  clearing  nozzle  "  could  be  devised  which  would  with- 
stand the  heat,  much  time  might  be  saved  which  is  now  necessarily  used  in  clearing 
the  nozzle. 


BURNING  THE  EGGS.  121 

as  the  fierce  heat  of  the  flame  would  fuse  it.  The  wooden 
cylinder  into  which  the  pipe  was  thrust  was  one  and  one- 
fourth  inches  in  diameter.  The  wood,  being  a  non-conductor 
of  heat,  was  of  great  convenience  in  handling  the  pole.  The 
end  of  the  pipe  was  fitted  with  a  cyclone  nozzle.  The  aper- 
ture of  this  nozzle  is  very  small,  hence  the  value  of  the 
strainer  before  mentioned,  which  prevents  the  entrance  of 
foreign  substances  with  the  oil  and  a  consequent  clogging 
of  the  nozzle.  The  two  men  handling  this  apparatus  filled 
the  tank  with  oil  and  then  carried  it  to  the  spot  where  the 
burning  was  to  be  done.  One  man  then  operated  the  pump 
while  the  other  handled  the  pole  and  nozzle.  As  soon  as  the 
pump  was  started  a  fine  spray  of  oil  was  thrown  into  the  air 
and  ignited  by  a  match.  By  means  of  the  pole  the  resulting 
fierce  flame  was  carried  among  the  undergrowth  and  over 
the  ground,  destroying  every  living  thing  in  its  path.  When 
this  work  was  carefully  done,  no  eggs  escaped  except  such 
as  were  hidden  in  ledges  or  holes  in  the  ground.  An  at- 
tempt was  made  also  with  this  apparatus  to  destroy  eggs 
which  had  been  deposited  in  stone  walls.  (See  Plate 
XVIII.)  Though  this  was  partially  successful  in  so  far  as 
the  fire  reached  and  destroyed  most  of  the  eggs,  those  which 
were  deposited  under  the  lower  stones  of  the  wall  were  un- 
harmed, even  though  in  many  cases  the  stones  were  cracked 
and  broken  by  the  heat.  As  it  sometimes  became  necessary 
to  use  this  apparatus  in  burning  out  walls  near  growing 
crops,  a  sheet-iron  screen  was  set  up  between  the  flame  and 
the  growing  vegetables  to  protect  them  from  the  heat,  being 
moved  along  the  wall  as  the  work  progressed.  Burning 
was  thus  done  without  any  resultant  injury  to  the  gardens. 
This  machine,  which  has  been  christened  the  "  cyclone 
burner,"  would  be  most  useful  in  checking  invasions  of 
crawling  pests  like  the  army  worm. 

Fire  was  also  used  in  hollow  trees,  the  eggs  hidden  within 
them  being  destroyed  by  burning  out  the  decayed  wood.  If 
this  is  judiciously  done,  there  will  be  no  injury  to  the  tree. 
Unless  great  care  is  used,  however,  to  extinguish  the  flame  in 
time,  there  is  much  danger  of  destroying  apple  trees  in  this 
way.  Cherry,  oak  and  willow  trees  have  rarely  been  injured 
by  burning  out  cavities ;  indeed,  some  old  trees  appear  to 


122  THE   GYPSY  MOTH. 

have  been  benefited  by  such  burning,  as  they  have  shown  a 
better  growth  during  the  season  following.  Oil  is  poured 
in  at  the  top  of  the  hollow,  and  a  sufficient  aperture  made 
at  the  bottom  to  ensure  a  good  draft.  The  oil  is  then 
lighted,  and  the  draft  in  the  funnel  thus  made  fans  the 
flame  until  the  decayed  wood  has  been  consumed.  This 
should  be  done  only  in  the  winter,  when  the  sap  is  dor- 
mant, and  the  fire  should  be  extinguished  before  it  has  done 
serious  injury  to  the  live  wood.  This  treatment  is  unnec- 
essary in  cavities  so  accessible  that  the  eggs  and  dead  wood 
may  be  removed  by  other  means. 

The  naphtha  burner,  an  instrument  commonly  used  by 
painters  and  plumbers,  was  used  in  1891  as  a  substitute  for 
the  scraping  of  eggs  from  trees  and  rocks,  which  sometimes 
resulted  in  their  being  scattered.  This  burner  is  supplied 
with  an  air  pump,  and  furnishes  an  air-blast  flame  of  an  ex- 
tremely fierce  heat.  If  this  flame  is  applied  directly  to  the 
egg-cluster,  it  will  reduce  it  to  ashes  on  the  tree,  although 
occasionally  eggs  exposed  to  such  great  heat  will  burst, 
possibly  scattering  others.  The  burner  should  be  used  only 
on  the  trunks  of  large  trees  having  thick  bark,  or  in  such 
cavities  in  trees  or  rocks  as  cannot  be  reached  by  other 
methods. 

Killing  the  Eggs  with  Chemicals. 

Early  in  the  work  of  1891  it  was  seen  to  be  impossible  to 
detach  the  egg-masses  from  their  various  places  of  deposit 
without  occasionally  scattering  and  losing  some  of  the  eggs. 
Experiments  made  during  the  following  winter  proved  that 
eggs  scattered  and  exposed  to  the  vicissitudes  of  the  season 
were  not  all  destroyed  by  frost  or  snow,  but  that  about  two- 
thirds  of  them  hatched  in  the  spring.  It  was  seen  that  it 
would  be  wiser  and  safer  to  destroy  the  eggs  without  re- 
moval, and  experiments  were  made  with  that  end  in  view. 
The  most  successful  method  at  first  used  was  the  application 
of  acids  which  in  combination  destroyed  the  eggs.  The 
apparatus  was  designed  and  the  method  invented  by  Mr. 
F.  C.  Moulton,  a  chemist  employed  in  the  gypsy-moth  work. 
The  apparatus  (Fig.  2)  was  composed  of  a  small  tin  case  hold- 
ing two  bottles,  each  of  them  having  a  rubber  stopper  with 
two  glass  tubes,  each  of  which  projected  into  the  bottle  as 


USE  OF  ACIDS  AND  CREOSOTE.  123 

well  as  out  at  the  top  of  the  cork,  where  it  was  bent  at  a 
right  angle.  One  of  the  tubes  in  each  bottle  was  drawn 
down  to  a  point  with  a  small  aperture, 
and  served  as  a  discharge  pipe.  The 
other  was  connected  with  a  rubber  tube 
having  a  mouth-piece  of  glass.  One 
of  the  bottles  held  a  mixture  of  phenol 
or  carbolic  acid  and  turpentine  (fifty 
per  cent,  of  each)  ;  the  other,  chemi- 
cally pure  nitric  acid.  By  blowing  into 
the  mouth-piece  of  the  bottle  containing 
the  carbolic  acid  mixture,  a  jet  of  this 
acid  was  thrown  upon  the  egg-mass. 
This  carbolic  acid  at  once  penetrated 
the  cluster  and  in  all  probability  de- 
stroyed the  life  of  the  eggs.  To  render  FIG  2  ?Acia  apparatus 
the  destruction  of  all  the  eggs  an  abso- 
lute certainty,  a  jet  of  nitric  acid  from  the  other  bottle  was 
then  thrown  in  the  same  manner  upon  the  mass.  While 
nitric  acid  of  itself  will  not  penetrate  the  egg-clusters,  it  is 
alone  sufficient  to  kill  the  eggs  if  they  are  divested  of  their 
hairy  covering  and  immersed  in  it.  The  two  acids  in  combi- 
nation reacted  and  produced  an  extreme  heat  and  corrosion, 
and  a  few  applications  entirely  destroyed  the  egg-cluster. 

While  this  apparatus  was  being  used  in  the  field,  experi- 
ments were  made  to  find  some  simpler  method  of  destroying 
the  eggs.  Although  the  acids  were  effective,  they  were 
expensive  and  there  was  some  danger  of  injuring  the  men 
using  them.  Clothes,  ropes,  tools  and  apparatus  were  also 
injured  by  the  fumes  of  acids  which  were  kept  with  them  in 
the  tool  boxes.  The  experiments  finally  resulted  in  the  choice 
for  use  in  the  field  of  a  cheap  creosote  oil  manufactured  by 
the  Carolina  Oil  and  Creosote  Company,  Wilmington,  N.  C. 
This  oil  was  recommended  for  trial  by  Prof.  N.  S.  Shaler. 
It  requires  neither  preparation  nor  complex  apparatus,  but 
can  be  drawn  from  the  barrel  into  cans  and  applied  with  a 
brush.  If  a  cluster  is  thoroughly  soaked  with  this  liquid,  it 
penetrates  and  kills  all  the  eggs,  and  is  very  effective  except 
in  the  coldest  weather,  when  it  may  sometimes  thicken.  It 
may  then  be  made  more  penetrative  by  being  mixed  with 


124 


THE   GYPSY  MOTH. 


carbolic  acid  and  turpentine,  as  follows :  creosote  oil,  fifty 
per  cent. ;  carbolic  acid,  twenty  per  cent. ;  spirits  of  turpen- 
tine, twenty  per  cent. ;  coal  tar,  ten  per  cent.  The  coal  tar 
is  always  added  to  color  the  egg-clusters,  so  that  those  which 
have  been  treated  may  be  distinguished.  The  creosote  itself 
is  not  strongly  colored,  and  often  fades  after  application, 
leaving  the  egg-clusters  of  their  original  color.  Tar  is  used 
in  preference  to  ordinary  pigments  because  it  mixes  well 
with  the  creosote,  and  does  not  settle  to  the  bottom  of  the  can 
but  is  held  in  suspension.  Almost  any  mixture  of  sufficient 
penetrative  qualities  and  containing  considerable  carbolic 
acid  will  kill  the  eggs. 

A  pocket  receptacle  has  been  devised  for  convenience  in 
carrying  paint  and  creosote  and  applying  them  to  infested 
objects.  This  consists  of  a  tin  can  or  box  (Figs.  3  and  4),  in 
which  two  tubes  are  fastened.  One  of  these  tubes  contains 
creosote  and  the  other  white  paint.  Each  of  these  tubes  is 
stopped  at  the  mouth  by  a  cork  through  which  the  handle  of  a 
small  paint  brush  is  thrust.  The  space  inside  the  can  and  about 
the  tubes  is  packed  with  cotton  waste  (Fig.  4),  which  receives 
all  drippings  from  the  tubes.  Paint  and  creosote  can  be 
carried  thus  in  the  pocket  with  little  danger  to  the  clothing. 


Paint  and  creosote 


FIG.  4.  A  sectional  view,  show- 
ing manner  of  packing. 


When  a  tree  or  other  object  is  found  infested,  it  is  marked 
with  paint  to  indicate  the  fact.  The  egg-clusters  are  then 
treated  with  the  creosote.  In  woodland  in  outer  towns  each 


*  Every  tool  issued  to  workmen  in  the  field  has  its  number  stamped  upon  it. 


PLATE  XIX.     Treating  egg-clusters  with  creosote. 


IMPLEMENTS   USED. 


125 


egg-cluster  when  treated  is  surrounded  with  a  ring  of  white 
paint  to  prominently  mark  its  location,  (see  Plate  XIX.). 

The  most  recent  preventive  method  used  in  Europe  is  the 
covering  of  the  eggs  with  a  coat  of  tar  or  with  raupenleim, 
a  substance  much  used  to  prevent  caterpillars  from  ascending 
trees.  Though  these  substances,  as  well  as  varnish,  have 
been  used  here  experimentally  with  some  success,  the  use 
of  creosote  oil  is  much  to  be  preferred,  as  it  penetrates  the 
eggs  at  once  and  destroys  their  life,  while  the  other  sub- 
stances merely  prevent  the  larvee  from  emerging,  provided 
the  covering  remains  intact. 

Destroying  the  Eggs  by  Gases. 

Experiments  were  made  to  find  some  agent  other  than  fire 
that  would  destroy  the  eggs  in  hollow  trees.  A  little  bro- 
mine or  chlorine  poured  into  the  hollow  of  a  tree,  branch  or 
stump  will  destroy  all  animal  life  within  the  hollow  if  the 
cavity  can  be  thoroughly  sealed  or  closed. 

Implements  used  in  the  Search  for  the  Eggs. 
Each  inspector  is  provided  with  a  small  binocular  glass  of 
opera  size,  which  he  carries  in  a  leather  case  suspended  by  a 
strap  from  his  shoulder.  By  means  of  this  he  is  able  while  on 
the  ground  to  distinguish  the  eggs  of  the  gypsy 
moth  from  those  of  other  insects  when  attached 
to  the  higher  limbs  of  large  trees.  This  glass 
is  useful  in  dark  or  cloudy  weather,  as  well  as 
in  the  morning  or  evening  twilight  of  the  short 
winter  days.  Its  use  often  renders  tree  climb- 
ing unnecessary,  and  thus  much  time  is  saved. 
Each  man  is  provided  with  a  pocket  mirror  so 
constructed  that  the  glass,  if  broken,  can  be 
quickly  and  cheaply  replaced  (Fig.  5).  This 
is  extremely  useful  in  many  ways  during  the 
search  for  eggs.  Whenever  the  lower  rail  of  a 
board  or  picket  fence  is  so  near  the  ground  that 
its  under  side  cannot  be  seen,  a  mirror  placed  at 
a  slight  angle  underneath  will  reflect  the  whole 
lower  surface  for  several  feet,  and  show  any 
egg-clusters  which  may  be  deposited  there. 


126  THE   GYPSY  MOTH. 

Mirrors  are  also  useful  in  reflecting  sunlight  into  the  holes  and 
cavities  of  trees  and  rocks,  so  as  to  determine  whether  or  not 
the  eggs  are  hidden  within  these  recesses.  Occasionally  hol- 
lows in  the  under  surfaces  of  high  lirnbs  are  inspected  from  the 
ground  by  the  combined  use  of  the  opera  and  hand  glasses, 
the  hand  glass  throwing  the  light  into  the  hollow,  and  the 
opera  glass  enabling  the  inspector  to  determine  its  contents. 
During  the  spring  of  1891  the  egg-clusters,  being  then 
very  numerous,  were  found  in  almost  every  conceivable 
situation.  They  were  deposited  on  the  under  surface  of 
steps,  under  piazzas,  floors,  beneath  the  baseboards  offences, 
in  hollow  fence  posts,  in  sheds,  out-buildings,  cisterns,  con- 
ductors, ventilators,  basements,  cellars,  chimneys  and  many 
other  places  both  within  and  without  dwellings.  Their  num- 
bers in  many  such  places  were  so  great  that  it  was  deemed 
unsafe  to  allow  them  to  hatch,  lest  the  caterpillars  should 
prove  very  destructive  before  their  ravages  could  be  stayed. 
Boards  were  therefore  removed 
from  fences,  steps  and  buildings, 
and  this  work  required  the  use  of 
such  implements  as  crow-bars, 
pinch-bars  and  hammers.  Dark 
lanterns  were  frequently  required 
FIG.  e.  Cleaning  knives.  jn  cellarS)  under  piazzas  and  in 
barns.  Special  knives  with  blades  bent  at  different  angles 
were  made  for  removing  the  eggs  from  the  recesses  of  fences 
and  trees.  With  the  aid  of  such  implements  most  of  the 
hidden  eggs  were  found  and  destroyed. 

THE  DESTRUCTION  or  CATERPILJUAES. 
When  the  larvae  first  emerge  from  the  eggs,  they  usually 
remain  for  several  hours  on  the  outside  of  the  egg-cluster, 
or  if  the  weather  becomes  cold  or  stormy,  for  two  or  three 
days.  While  in  this  position  they  may  be  quickly  destroyed 
by  the  flame  of  a  naphtha  burner  or  by  an  application  of 
creosote  or  kerosene. 

Banding  Trees. 

After  the  eggs  on  trees  have  been  destroyed,  the  young 
caterpillars  which  hatch  elsewhere  may  be  kept  from  ascend- 


BANDING  TREES.  127 

ing  the  trees  by  encircling  the  trunks  with  some  appliance 
or  substance  which  the  larvae  cannot  cross.*  The  protection 
of  large  trees  by  banding  is  most  important  as  their  size 
favors  the  distribution  of  the  moth,  rendering  it  both  diffi- 
cult and  expensive  to  care  for  them. 

Such  trees  are  often  situated  near  buildings,  lumber  piles, 
ledges,  accumulations  of  loose  rock  or  other  objects  which 
offer  many  hiding  places  to  the  caterpillars  and  other  forms 
of  the  gypsy  moth.  Occasionally  sheds  or  hencoops  are 
built  about  the  trunks  of  trees.  When  such  places  of  shelter 
as  are  not  readily  accessible  to  the  workmen  are  thus  offered 
to  the  moth,  the  caterpillars  must  be  prevented  from  ascend- 
ing the  trees,  and  either  destroyed  by  starvation  or  driven 
to  other  quarters.  Where  there  is  no  other  vegetation  near, 
this  may  be  accomplished  by  banding  the  trees  in  the  early 
spring.  If  there  is  no  other  food  in  the  vicinity,  the  young 
caterpillars  prevented  from  ascending  the  trees  will  starve. 
If  there  are  other  trees  within  crawling  distance  which  are 
so  located  and  environed  as  to  have  no  shelter  about  them 
inaccessible  to  man,  the  migration  of  the  caterpillars  thither 
will  facilitate  their  destruction  by  the  workmen.  In  wood- 
lands, if  the  eggs  upon  the  trees  are  destroyed  and  the  trees 
well  banded  previous  to  the  hatching  of  eggs,  which  may  have 
been  overlooked  on  the  ground,  and  all  vegetation  on  the 
ground  is  killed  by  means  of  the  cyclone  burner  soon  after 
the  caterpillars  appear,  extermination  will  result.  The 
method  of  burning  caterpillars  in  infested  brush  is  shown 
in  Plate  XX. 

Bands  are  most  useful  for  these  purposes  when  put  on  just 
before  the  young  caterpillars  appear.  They  will  then  be 
fresh  and  sticky  when  the  young  larvae  are  weak  and  unable 
to  crawl  far  if  deprived  of  the  sustaining  and  strengthening 
nourishment  which  they  eagerly  seek.  Before  the  hatching 
of  the  eggs  in  1891  and  1892  many  of  the  large  street  trees 
in  Maiden  and  Medford  and  some  in  Somerville  were  banded 
with  strips  of  tarred  paper.  This  work  was  first  undertaken 
in  Medford.  It  was  proposed  by  the  selectmen  of  that  town 
as  a  means  of  protecting  the  trees  from  the  gypsy  moth  and 

*  In  1891  bands  of  loose  cotton  batting  were  experimented  with  for  this  purpose, 
bat  they  did  not  prevent  the  larger  caterpillars  from  ascending  the  trees. 


328  THE   GYPSY  MOTH. 

the  canker-worm,  and  a  part  of  the  expense  was  borne  by 
the  town.  The  bark  of  the  tree  was  first  scraped  or  planed 
at  a  height  of  about  six  feet  from  the  ground,  so  that  a 
reasonably  smooth  surface  about  six  inches  wide  was  formed 
extending  around  the  trunk.  A  band  of  cotton  waste  was 
then  placed  on  the  smooth  surface  about  the  trunk,  and  a 
band  of  tarred  paper  about  the  cotton.  A  cord  about  the 
paper  drew  it  closely  to  the  cotton  waste,  which  was  thus 
pressed  firmly  against  the  tree.  This  waste  was  placed 
beneath  the  paper  to  prevent  the  newly  hatched  caterpillars 
(which  can  pass  through  very  minute  crevices)  from  crawling 
under  it  and  so  on  up  the  tree.  The  tarred 
paper  was  then  covered  with  a  mixture  con- 
sisting of  three  parts  tree  ink,  one  part  pine 
tar  and  one  part  petroleum  (residuum  oil) . 
The  cotton  waste  prevented  this  mixture 
from  penetrating  to  the  bark  of  the  tree. 
Fig.  7  shows  the  band  about  the  tree  with 
the  string  removed  and  a  piece  torn  away 
to  show  the  cotton  packing.  The  black 
FIG.  7.  Tarred  paper  band  represents  that  part  of  the  paper 
band.  which  was  covered  with  the  mixture. 

Tacks  and  staples  were  used  where  necessary  to  draw  the 
paper  and  string  closely  to  the  tree. 

It  was  necessary  at  first  to  apply  several  coats  of  the  mixt- 
ure, so  that  the  tarred  paper  might  become  so  well  saturated 
that  it  would  not  absorb  subsequent  applications.  When 
this  was  effected,  an  application  was  made  at  least  twice  a 
week  for  the  rest  of  the  season  where  trees  on  dusty  streets 
were  banded,  but  it  was  not  required  so  often  (except  in  very 
hot,  dry  weather)  in  orchards  or  woodland.  As  a  result  of 
the  banding,  most  of  the  caterpillars  were  kept  out  of  trees 
along  the  streets,  and  therefore  there  was  little  danger  of 
their  being  distributed  along  the  highways  in  such  numbers 
as  in  former  years.  In  badly  infested  localities  this  method 
can  only  be  effective  when  the  eggs  on  the  trees  have  been 
destroyed  and  a  large  part  of  the  egg-clusters  in  the  vicinity 
gathered.  Otherwise,  the  massing  caterpillars  will  bridge 
the  tarred  paper  with  their  bodies  and  on  this  bridge  others 
will  cross,  or  else  the  young  caterpillars  will  be  borne  on  the 


THE  USE   OF  INSECT  LIME.  129 

wind  from  the  branches  of  one  tree  to  those  of  another,  ren- 
dering all  precautions  useless. 

In  banding,  all  poles,  dead  trees  and  other  objects  which 
in  any  way  communicate  with  banded  trees  must  be  removed 
or  banded.  Where  the  limbs  of  trees  touch  houses,  fences, 
rocks  or  the  earth,  they  must  be  so  trimmed  as  to  prevent 
such  contact.  Unless  all  such  means  of  communication  are 
cut  off,  banding  will  not  produce  the  desired  effect.  Much 
discrimination  must  be  used  in  banding  trees  in  cultivated 
lands,  lest  the  caterpillars  be  driven  from  trees  and  scattered 
abroad  among  shrubbery,  weeds  or  garden  crops,  where  they 
cannot  be  so  readily  dealt  with. 

Raupenleim  Bands. 

In  1891  Mr.  B.  F.  Fernow,  chief  of  the  Division  of  For- 
restry  of  the  United  States  Department  of  Agriculture, 
recommended  that  "raupenleim"  or  "insect  lime,"  a  Ger- 
man preparation  for  the  protection  of  trees,  be  used  in  this 
work.*  A  sample  was  ordered,  but  it  arrived  too  late  in 
the  season  to  be  experimented  with  that  year.  In  1892 
experiments  were  made,  and  later  thirteen  and  one-half  tons 
of  the  "leim"  were  ordered  and  used  in  banding  40,704 
trees  during  that  season  and  the  next.  The  raupenleim  used 
in  1892  was  very  effectual,  but  much  of  the  importation  of 
1893  was  apparently  inferior  in  quality  to  that  used  the 
previous  year,  and  the  results  obtained  were  anything  but 
gratifying.  If  results  similar  to  those  of  1892  can  be  secured, 
this  material  will  be  of  great  value  for  use  in  this  country 
against  such  insects  as  the  canker-worms,  which  pupate  in 
the  ground  and  whose  female  imagoes  are  wingless. 

Raupenleim  was  used  in  the  gypsy-moth  work  to  take  the 
place  of  the  tarred  paper  bands.  The  advantages  obtained 
from  its  use  are  that  when  of  a  good  quality  and  properly 
placed  upon  the  tree,  it  will  remain  soft  and  viscid  for  several 
months,  and  during  that  time  will  prevent  the  ascent  of 
nearly  all  larvae  and  also  wingless  female  imagoes.  The  sub- 

*  Raupenleim,  translated  literally,  would  read  "  caterpillar  glue."  According  to 
Webster,  lime  (a  viscous  substance)  is  akin  to  the  German  word  "leim."  It  is 
used  here  in  connection  with  the  word  insect  in  much  the  same  sense  as  it  is  used 
in  connection  with  bird  as  "bird-lime." 


130  THE   GYPSY  MOTH. 

stance  has  been  used  abroad,  especially  in  Germany,  for 
several  years  past.  The  government  forestry  authorities  of 
Bavaria  employ  it  to  prevent  the  ascent  of  the  nun  moth. 
This  insect  in  1890  devastated  the  German  forests  to  such 
an  extent  that  "three  thousand  men  were  employed  to  check 
its  ravages,  and  in  one  instance  it  was  necessary  to  cut  and 
burn  a  strip  of  timber  four  miles  broad  by  five  miles  long  to 
prevent  further  devastation."  * 

It  was  ascertained  by  experiment  that  the  application  of 
this  insect  lime  did  not  injure  the  trees,  nor  has  any  injury 
been  observed  to  trees  where  it  has  been  used  in  this  country. 
Though  the  death  of  three  or  four  young  trees  has  been 
reported  and  credited  to  the  injury  caused  by  liming,  it  is 
possible  that  the  primary  injury  was  caused  by  too  deep  scrap- 
ing of  the  bark.  In  such  a  case  the  oil  contained  in  the  lime 
might  penetrate  the  liber  and  cambium  of  the  inner  bark  and 
eventually  destroy  the  life  of  the  tree.  There  is  no  necessity 
for  scraping  a  smooth-barked  tree.  Though  over  40,000 
trees  have  been  banded  in  the  work  in  Massachusetts,  these 
are  the  only  cases  where  injury  is  believed  to  have  resulted. 
This  agrees  with  the  experience  of  the  foresters  in  Ger- 
many, f 


*  Dr.  E.  Hartig  in  "  Forstlich  —  naturwissenchaftliche  Zeitschrift,"  January, 
1892. 

t  "  The  excellent  results  of  the  lime-rings  for  the  prevention  of  larvae  ascending 
the  stem  and  feeding  on  the  foliage  of  our  forest  trees  has  been  proven  during  the 
past  ten  years.  Not  content  with  this,  however,  —  for  it  became  our  duty  to  see  if 
the  lime  itself  did  not  injure  the  tree,  —  we  examined  the  different  layers  of  the  bark, 
and  can  confidently  assert  that  no  harm  to  the  most  tender  trees  has  been  done  by 
liming  them. 

"  We  firmly  believe  that  the  man  who  scrapes  the  bark  off  the  trees  can  do  more 
harm  in  one  hour  than  he  could  by  ringing  trees  with  lime  the  rest  of  the  year ;  and 
we  would  therefore  recommend  for  the  work,  men  who  know  the  difference  between 
the  inner  and  outer  bark  of  trees  infested,  and  especially  warn  them  to  be  careful  of 
smooth-barked  trees,  from  which  they  have  to  remove  only  such  mosses  and  lichens 
as  are  found  on  them.  On  the  trees  —  Dr.  R.  Hartig  says  —  that  were  limed  twenty- 
five  years  ago  no  bad  results  have  been  observed.  In  fact,  on  the  part  of  the  tree 
where  the  ring  was  laid  on,  the  growth  of  wood  was  larger  than  either  above  or  below, 
which  he  ascribes  to  the  action  of  the  lime  on  the  outer  bark,  softening  it  somewhat 
and  giving  freer  circulation  of  the  sap  in  the  inner  bark. 

"  Only  in  instances  where  the  bark  was  scraped  to  the  quick  has  the  lime  pene- 
trated, and  therefore  all  harm  must  be  ascribed  to  the  scraping  knife  and  not  to  the 
lime. 

"  There  is,  therefore,  no  occasion  for  alarm  as  regards  the  ringing  of  trees  with 
insect  lime  to  preserve  them  from  the  ravages  of  insects  of  all  kinds."— (Translated 
from  "  Forstlich— naturwissenchaftliche  Zeitschrift,"  July  7, 1892.) 


LIME  MACHINES.  131 

A  variety  of  machines  have  been  devised  in  Europe  for 
applying  raupenleim  to  the  trees.  One  of  these,  the  "  Eich- 
horn  machine"  (Fig.  8*),  was  imported  by  the  Board  and 
was  used  to  some  extent.  It 
consists  of  a  triangular  wooden  (_ 
box  with  two  handles,  one  of 
which  is  hinged  and  acts  as  a 
lever.  At  the  apex  of  the  box 
is  an  aperture  of  the  size  de- 
sired for  applying  the  lime  to 
the  trunk  of  the  tree.  This 
receptacle  being  first  filled 
with  lime,  a  handle  is  grasped 

in  each  hand  Of  the  Workman,  FIG.  8.    The  Elchhorn  machine. 

who,  by  pressure  brought  to  bear  on  both  handles,  forces  the 
contents  through  the  opening.  In  the  mean  time  the  machine 
is  passed  around  the  trunk,  and  a  band  of  lime  adheres  to 
the  bark.  This  machine  can  be  used  to  advantage  where  the 
rings  are  put  on  at  a  height  of  three  or  four  feet  from  the 
ground ;  but  where  it  is  necessary  to  place  them  at  a  height 
of  six  feet  or  more,  as  on  street  trees,  great  strength  is 
required  to  force  the  lime  out,  and  the  use  of  the  machine  is 
not  practicable.  In  the  machine  as  imported  the  aperture 
through  which  the  lime  passed  was  about  one-fourth  of  an 
inch  in  width  and  one  and  one-half  inches  in  length.  It  was 
found  by  experiment  that  the  lime  remained  viscid  for  a 
longer  time  and  was  more  effective  in  stopping  the  ascent  of 
the  gypsy-moth  caterpillars  if  the  band  was  made  wider  than 
the  length  of  this  opening,  and  of  greatest  thickness  on  the 
lower  edge ;  consequently  the  opening  of  each  machine  was 
enlarged  to  such  dimensions  as  to  deposit  a  band  on  the  tree 
about  one-half  inch  in  thickness  on  the  lower  edge  and  two 
and  one-half  inches  in  width.  The  lime  could  be  so  put  on 
by  trowels  or  spades  made  for  the  purpose  that  the  lower 
edge  of  the  band  projected  more  than  half  an  inch  from  the 
bark.  If  this  lower  edge  was  made  even  thicker  than  this, 
and  shaped  at  an  acute  angle,  the  oil,  which  gradually  tried 
out  from  the  surface  of  the  band  when  exposed  to  the  sun- 

*  See  also  the  single-handed  Eichhorn  machine,  Plate  XXII.,  Fig.  4. 


132  THE   GYPSY  MOTH. 

light,  would  trickle  down  to  the  edge  and  hang  there,  form- 
ing an  impassable  obstacle  to  the  caterpillars.  The  intent 
of  the  lime  bands  used  in  the  work  on  the  gypsy  moth  was 
to  prevent  any  caterpillars  from  ascending  the  trees.  If  a 
few  reached  the  branches  and  remained  in  the  trees,  passed 
through  their  transformations  and  laid  their  eggs,  it  is  obvious 
that  the  bands  would  be  worthless  for  the  purpose  for  which 
they  were  intended,  though  even  then  they  might  be  useful 
in  controlling  certain  other  caterpillars  which  frequently 
spin  or  drop  to  the  ground,  as  they  would  prevent  most  of 
them  from  reascending  the  tree.  But  in  a  case  where  exter- 
mination is  sought,  and  destruction  of  all  gypsy  caterpillars 
is  a  consequent  necessity,  it  is  imperative  to  prevent  their 
ascending  large  trees.  Quite  frequently  the  bands  were 
injured  or  displaced  in  some  way  by  people  or  animals 
brushing  against  them,  and  often  leaves  or  twigs  from  the 
trees  dropped  and  stuck  upon  the  bands,  forming  bridges  over 
which  the  caterpillars  could  climb.  To  lessen  the  chances  of 
their  reaching  the  branches,  two  or  even  three  bands  were 
sometimes  put  upon  the  same  trunk,  one  above  the  other.* 
The  same  thing  has  been  done  in  Germany  during  great 
invasions  of  the  nun  moth  (Liparis  monacha),  and  for  this 
purpose  a  machine  has  been  devised  for  applying  insect  lime 
at  a  greater  height  on  trees  than  could  be  otherwise  reached 
by  hand  from  the  ground. 

The  Hochleim  machine  (Plate  XXI.,  Fig.  l)f  is  a  tin 
cylinder  attached  to  a  long  pole.  A  top  that  acts  as  a  plunger 
is  fitted  to  the  cylinder  and  may  be  depressed  by  pulling  on 
a  cord  that  is  fastened  to  a  strong  spiral  spring.  This  spring 
is  connected  with  iron  wires  which  are  attached  to  the  upper 
part  of  the  machine.  When  this  is  depressed,  the  lime  is 
forced  out  at  the  bottom  of  the  machine  through  a  round  hole 
bored  in  a  brush  which  is  fastened  to  one  side,  as  seen  in  the 
figure.  The  lime,  which  must  necessarily  be  of  a  more  or 
less  liquid  consistency,  is  applied  around  the  trunk  of  the 


*  This  would  not  be  ordinarily  necessary  in  protecting  trees  against  attacks  of 
native  caterpillars. 

f  Figures  of  the  implements  and  machines  appearing  on  plates  XXI.  and  XXII. 
have  been  previously  published,  together  with  others,  in  "Die  Nonne,"  by  Dr.  H. 
Nitsche,  Ed.  Holzel's  Verlag,  Vienna,  1892. 


PLATE  XXI. 


PLATE  XXII. 


Fig.l 


Fig. 3 


Pig.  5 


LIME  MACHINES.  133 

tree  with  the  brush.  The  tools  (Plate  XXI.,  Fig.  2,  a,  6,  c) 
are  also  attached  to  poles,  and  are  used  for  scraping  and 
smoothing  the  bark  at  a  height.  Tool  c  has  a  scraper  upon 
one  side  and  a  stiff  brush  upon  the  other.  The  lime  hose 
(Plate  XXI.,  Fig.  4)  is  an  elongated  cone-shaped  bag  made 
from  some  thick  fabric.  It  has  a  mouth-piece  at  the  small  end 
for  the  outlet  of  the  lime,  while  on  the  large  end  is  attached 
a  tin  ring  or  cover,  by  means  of  which  the  bag  may  be  filled 
and  closed.  This  apparatus  is  carried  by  a  strap  or  band 
passing  over  the  right  shoulder,  and  the  lime  is  squeezed  out 
by  forward  pressure  of  the  right  hand.  It  is  inexpensive, 
easily  carried  and  durable ;  still,  it  cannot  be  entirely  satis- 
factory, as  the  oil  with  which  the  lime  is  mixed  will  gradually 
work  through  the  fabric  and  soil  the  clothing  of  the  workman. 

The  Eck  lime  hose  is  illustrated  also  (Plate  XXI.,  Fig.  5), 
but,  as  the  filling  is  done  at  the  smaller  end,  requiring  an 
expensive  apparatus  for  forcing  the  lime  in,  it  would  hardly 
seem  a  desirable  machine,  although  its  cost  in  Germany  is 
small  (1  mark,  about  25  cents).  A  very  simple  machine  is 
a  large  tin  cylinder  (Plate  XXI.,  Fig.  6)  with  a  piston,  the 
handle  of  which  is  pushed  in  by  the  man  using  it,  who  in 
this  way  drives  the  lime  through  the  tin  mouth-piece.  This 
mouth-piece  can  be  removed  and  others  of  different  sizes  can 
be  substituted,  according  to  the  thickness  and  shape  of  the 
lime  ring  desired. 

The  Seitz  lime  machine  (Plate  XXII. ,  Fig.  2)  is  a  large  tin 
apparatus  holding  about  two  and  one-half  quarts.  The  cover 
is  fastened  with  a  "bayonet"  lock.  The  piston,  which  is 
geared,  is  worked  back  and  forth  by  a  geared  wheel  or  cog 
fastened  to  the  cover,  and  turned  by  a  handle.  This  larger  ap- 
paratus, rather  heavy  when  filled,  is  carried  crosswise  in  front 
of  the  workman,  who  turns  the  handle  with  his  right  hand. 

The  Hauenstein  lime  machine  (Plate  XXII.,  Fig.  3)  is 
operated  on  the  same  principle  as  the  last,  except  that  the 
piston  is  driven  forward  by  spring-power.  The  tin  mouth- 
piece is  connected  with  the  main  body  of  the  machine  by  a 
piece  of  hemp  hose,  which  is  movable.  The  spring  is  drawn 
by  the  aid  of  a  wire  rope  with  a  loop  at  its  end.  The  work- 
man sets  his  foot  in  the  loop,  draws  the  machine  upward  and 
so  draws  the  spring,  which  is  arrested  by  a  snap  latch.  The 


134  THE   GYPSY  MOTH. 

machine  is  then  filled.  When  in  use  the  spring  is  released 
from  the  latch.  Like  the  other  machines,  this  machine  is 
carried  by  a  harness  or  carrying  band. 

A  simple  utensil  (Plate  XXII.,  Fig.  1)  is  like  the  "Eich- 
horn"  machine,  a  lime  "  squeezer,"  and  consists  of  a  wedge- 
shaped  box,  one  side  of  which  is  movable  and  may  be  pressed 
into  the  opening  formed  by  the  four  stationary  walls  of  its 
other  sides.  Spades  or  trowels  (Plate  XXI.,  Fig.  3,  a,  b,  c) 
are  often  used  to  apply  the  lime  and  shape  the  bands  where 
the  work  is  done  by  hand.  Where  a  number  of  men  are  at 
work,  a  lime  hod  (Plate  XXII.,  Fig.  5)  is  also  used.  This 
hod  is  carried  by  one  man,  who  keeps  several  others  supplied 
with  the  lime. 

There  are  some  disadvantages  in  the  use  of  insect  lime. 
It  is  not  cleanly,  as  under  a  hot  sun  more  or  less  running  oil 
exudes,  especially  on  smooth-barked  trees.  Unless  placed 
at  a  considerable  height  from  the  ground,  cattle  and  horses 
frequently  rub  against  it,  plastering  their  coats  in  a  very 
disagreeable  manner.  Complaints  have  been  occasionally 
received  that  pet  cats  returning  from  excursions  up  the  tree 
trunks  have  "tracked"  the  insect  lime  over  their  owners' 
carpets.  Notwithstanding  all  care  that  has  been  used  in  the 
application  of  the  material,  certain  spring  overcoats  and  fine 
shawls  have  been  ruined  when  the  owners  of  these  garments 
carelessly  leaned  against  trees  which  had  been  banded.  The 
insect  lime  does  not  adhere  well  to  trees  when  they  are  wet, 
and  occasionally  heavy  showers  will  cause  it  to  drop  off  in 
lumps.  These  lumps  when  trod  upon  adhere  to  the  shoes 
and  are  sometimes  a  source  of  considerable  annoyance  to 
housekeepers.  Such  accidents  may  be  avoided  by  applying 
the  lime  when  the  trees  are  dry,  and  by  forming  the  band 
with  its  upper  edge  bevelled  toward  the  tree  so  as  to  shed 
water.  It  is  then  not  likely  to  be  displaced  by  rains. 

If  the  lime  is  used  on  trees  standing  on  lawns,  it  is  likely 
to  prove  a  source  of  unpleasantness.  Some  complaints  in 
regard  to  this  have  been  received  from  owners  of  lawns  and 
croquet  grounds.  Such  objections  to  its  use  will  apply,  how- 
ever, to  any  material  of  the  kind,  and  are  not  to  be  avoided 
as  the  lime  is  ordinarily  used.  It  is  sometimes  recommended 
to  place  a  band  of  stiff  paper  about  the  tree,  turn  up  the 


LIME  AND  DENDKOLENE.  135 

lower  edge  in  such  a  way  as  to  form  a  trough  and  then  apply 
the  lime  upon  this.  If  this  band  of  paper  is  placed  at  a 
considerable  height,  it  may  prevent  many  of  the  disagreeable 
accidents  which  otherwise  frequently  happen.  Thus  far  we 
have  had  no  experience  in  applying  the  lime  in  this  manner. 

Other   Uses  for  Insect  Lime. 

Dr.  John  B.  Smith,  entomologist  of  the  New  Jersey  Ex- 
periment Station,  in  a  paper  read  by  him  as  president  of  the 
Association  of  Official  Economic  Entomologists  at  a  meet- 
ing of  that  society  held  Aug.  27,  1895,  in  connection  with 
the  meeting  at  Springfield  of  the  American  Association 
for  the  Advancement  of  Science,  gave  the  results  of  his 
experiments  with  raupenleim  and  a  similar  material,  "den- 
drolene."*  Dendrolene  was  invented  by  Prof.  F.  L.  Nason 
of  New  Brunswick,  who,  at  the  request  of  Dr.  Smith,  experi- 
mented with  a  view  of  obtaining  a  material  of  home  manu- 
facture possessing  the  insecticide  and  protective  properties 
of  the  raupenleim.  According  to  Dr.  Smith,  raupenleim  and 
dendrolene  are  both  crude  petroleum  products,  though  the 
raupenleim  has  some  admixture  of  a  substance  resembling  tar 
in  color  and  odor ;  but  in  both  cases  the  base  is,  or  seems  to 
be,  a  very  crude  or  impure  vaseline,  which  has  the  appearance 
of  the  base  of  such  lubricating  mixtures  as  wheel-grease. 
Dr.  Smith  has  used  both  substances  on  trees  to  prevent 
both  the  entrance  and  the  emergence  of  certain  tree  borers. 
So  far  he  has  seen  no  injury  to  the  tree  resulting  from  the 
use  of  either  material,  even  when  large  areas  of  bark  were 
covered.  While  the  raupenleim  seemed  more  effective 
against  borers,  the  dendrolene  remained  soft  longer,  making, 
as  Dr.  Smith  says,  "a  perfect  barrier  against  insects 
attempting  to  cross  it."  He  also  says  that  "  such  materials 
may  be  employed  against  scale  insects  on  comparatively 
small  trees  where  they  cover  only  the  trunks  and  larger 
branches,  and  where  even  a  thin  coating  applied  with  a  brush 
early  in  the  season  before  the  eggs  have  hatched  or  before 
reproduction  has  begun  in  the  case  of  the  viviparous  species, 
will  absolutely  prevent  the  emergence  of  young.  The  appli- 

*  See  Bulletin  of  Experiment  Station,  New  Jersey  Agricultural  College,  No.  Ill, 
Sept.  16,  1895. 


136  THE   GYPSY  MOTH. 

cation  of  a  coating  on  the  trunks  of  peach  trees  made  early 
in  the  season  will  prevent  oviposition  by  the  adult  of  the 
peach  tree  borer."  But  it  may  be  questioned  how  far  this 
covering  the  bark  with  such  a  material  can  be  carried  with- 
out eventually  injuring  the  tree.  Our  experiments  go  to 
prove  that  raupenleim  will  usually  prevent  the  ascent  of 
the  female  canker-worm  moth.  It  is  quite  probable,  however, 
that  after  wet  or  cold  weather,  some  of  the  moths  may  cross 
the  band  before  the  warmth  of  the  sun  has  rendered  it  viscid, 
as  the  lime  hardens  somewhat  in  such  weather  and  does  not 
again  become  soft  until  affected  by  the  sun's  warmth. 
Climbing  cutworms  and  many  other  caterpillars  have  been 
caught  on  the  bands.  Most  insects,  however,  seem  to  prefer 
to  turn  back  rather  than  attempt  to  cross.  The  larger  gypsy- 
moth  caterpillars  will  cross  when  the  bands  have  become 
somewhat  hardened  by  rain  or  cool  weather,  but  the  smaller 
caterpillars  seldom  crawl  over  the  bands.  The  raupenleim 
was  therefore  very  useful  for  banding  trees  which  had  been 
cleared  of  the  moth,  providing  the  young  caterpillars  could 
be  destroyed  by  fire  or  other  means  before  they  attained 
sufficient  size  and  strength  to  cross  the  lime.  The  bands  are 
useful  also  in  preventing  the  ascent  of  such  common  pests 
as  the  tent  caterpillar  and  tussock  moth  after  trees  have  been 
cleared  of  the  caterpillars  or  eggs  of  these  species.  *  Dr.  Smith 
says  that  as  a  protection  against  mice  and  hares,  "dendro- 
lene  will  serve  an  entire  season  when  put  on  one-fourth  of  an 
inch  thick  or  more."  As  much  cannot  be  said  of  the  raupen- 


»  The  application  of  bands  of  insect  lime  appears  to  prevent  the  common  tent 
caterpillars  from  crawling  either  op  or  down  trees.  A  wild  cherry  tree  which  con- 
tained a  great  number  of  these  caterpillars  was  banded  with  insect  lime.  When  the 
caterpillars  had  devoured  all  the  foliage  upon  the  tree  they  crawled  down  the  trunk 
to  the  band  and  there  remained  clustering  upon  the  trunk  within  two  feet  of  the 
upper  edge  of  the  band,  where  they  died,  apparently  of  starvation.  This  would 
indicate  that  by  banding  worthless  trees  infested  by  this  insect  it  might  be  prevented 
from  migrating  to  other  trees,  and  compelled  to  perish  from  lack  of  suitable  food.  Yet 
no  instance  of  this  kind  has  been  observed  with  any  other  insect,  and  no  record  was 
kept  of  the  number  of  caterpillars  originally  on  the  tree,  so  it  is  impossible  to  tell 
how  many  may  have  escaped.  It  is  not  safe  to  base  any  conclusions  on  a  single 
observation  of  this  sort.  It  is  given  here  merely  to  show  the  necessity  of  further 
observation  and  experiment  with  insect  lime,  which  can  probably  be  used  in  many 
ways  as  a  preventive  to  insect  attacks  or  an  insecticide  application. 

The  application  of  the  insect  lime  to  epg-clusters  has  already  been  mentioned 
(page  125) ,  but  it  has  been  superseded  in  Massachusetts  by  more  economical  and 
effective  measures  (page  123). 


SPRAYING.  137 

leim  used  for  the  gypsy-moth  work,  although  the  best  of  it 
remained  in  good  condition  from  one  to  three  months ;  yet 
in  some  cases  it  became  necessary  to  make  two  or  three  ap- 
plications during  a  season.  During  windy  weather  bands 
upon  dusty  streets  require  frequent  attention  and  occasional 
renewal.  Dr.  Smith  says  that  in  no  case  has  he  ever  ob- 
served any  injurious  effect  of  dendrolene  upon  the  trees. 

Dendrolene  is  supplied  by  Prof.  F.  L.  Nason,  New  Bruns- 
wick, N.  J.  Insect  lime  can  be  obtained  of  the  Bowker 
Fertilizer  Company,  Boston,  Mass.,  and  of  Wm.  Menzel  & 
Son,  New  York. 

Spraying  with  Paris  Green. 

When  the  second  commission  began  work  in  the  spring 
of  1891,  it  was  learned  that  the  efficacy  of  Paris  green  as  an 
insecticide  for  the  gypsy  moth  was  doubted  by  many  people 
in  Medford.  Experiments  were  therefore  immediately  begun 
to  determine  whether  spraying  with  Paris  green  would  kill 
the  caterpillars.  In  April  young  caterpillars  were  hatched 
by  artificial  means  in  the  office  of  the  commission  and  fed 
upon  leaves  which  had  been  carefully  sprayed  with  a  solution 
consisting  of  one  pound  of  Paris  green  to  one  hundred  and 
fifty  gallons  of  water.  Not  only  was  the  ordinary  Paris 
green  experimented  with,  but  samples  of  finely  bolted  poison 
were  secured.  The  experiments  showed  that  the  use  of 
either  quality  of  Paris  green  caused  death.  It  was  noticed, 
however,  that  the  caterpillars  which  ate  the  leaves  sprayed 
with  the  pulverized  poison  died  soon  after  beginning  to  feed, 
or  within  twenty-four  hours ;  while  those  which  ate  of  the 
leaves  sprayed  with  the  ordinary  Paris  green  lived  for  several 
days,  very  few  dying  within  twenty-four  hours.  The  ma- 
jority lived  three  or  four  days  and  some  even  a  longer 
time.  Samples  of  both  the  pulverized  and  ordinary  Paris 
green  were  analyzed  and  the  analyses  gave  substantially  the 
same  amount  of  arsenic  in  each.  From  this  it  would  appear 
that  both  were  equally  poisonous.  Why  they  were  not 
equally  effective  has  not  been  fully  determined.  But  as  the 
ordinary  Paris  green  was  made  up  of  fine  crystals  which  were 
more  or  less  insoluble,  while  a  larger  proportion  of  the  finely 
powdered  Paris  green  was  apparently  soluble  in  water,  the 


138  THE   GYPSY   MOTH. 

latter  would  be  more  quickly  dissolved  in  the  digestive 
fluids  of  the  caterpillars.  This  subject,  however,  needs 
more  scientific  investigation,  as  the  experiments  made  were 
too  limited  in  scope  to  allow  any  conclusions  to  be  based 
on  the  results.  As  it  was  found  later  that  neither  brand 
of  Paris  green  gave  as  satisfactory  results  in  the  field  as 
had  been  obtained  in-doors,  and  as  the  use  of  this  arsenite 
was  finally  given  up,  the  subject  of  the  comparative  efficiency 
of  the  pulverized  and  the  ordinary  Paris  green  was  not 
further  investigated. 

The  results  obtained  by  in-door  experiments  with  the  pul- 
verized Paris  green  led  to  experiments  on  a  larger  scale  in 
the  field  and  accordingly  a  ton  of  this  poison  was  purchased. 
Early  in  May  spraying  in  the  field  was  begun  (see  page  55). 
Most  of  the  sprayers  were  supplied  with  the  fine  Paris  green, 
which,  though  not  proving  as  efficacious  as  in  the  laboratory, 
nevertheless  killed  many  of  the  smaller  caterpillars.  As  the 
spraying  continued  it  was  observed  that  a  considerable  pro- 
portion of  the  caterpillars  of  middle  age  were  also  destroyed. 
Sometimes,  though  rarely,  persistent  spraying  appeared  to 
destroy  most  of  the  larger  caterpillars.  By  this  time  it  had 
been  determined  by  experiments  in  the  laboratory  that  Paris 
green  would  not  kill  all  the  larger  larvae ;  yet  as  it  had 
given  better  results  than  any  other  insecticide,  it  was  thought 
best  to  continue  its  use  at  varying  proportions  in  the  field, 
and  the  poison  was  used  at  a  strength  of  from  one  to  four 
pounds  to  one  hundred  and  fifty  gallons  of  water.  As  a 
rule  the  spraying  did  not  seriously  burn  the  foliage  when  a 
solution  was  used  consisting  of  one  pound  of  Paris  green  to 
one  hundred  and  fifty  gallons  of  water;  but  with  larger 
proportions  of  poison  the  foliage  was  considerably  burned. 
The  injury  developed  so  rapidly  that  within  a  short  time  the 
leaves  were  all  killed  and  the  surviving  larvae  were  obliged  to 
go  elsewhere  to  feed.  Therefore,  a  strong  Paris  green  mixt- 
ure had  little  better  effect  than  a  weak  one.  Lime  was 
then  used  with  the  Paris  green  with  a  view  of  neutralizing 
the  burning  but  considerable  injury  to  the  foliage  still  con- 
tinued. 

Though  even  when  three  or  four  pounds  of  the  Paris  green 
were  used  to  a  tank  of  water,  many  of  the  larger  feeding 


EFFECTS   OF   SPRAYING.  139 

caterpillars  survived.  Yet  a  difference  in  the  effect  of  the 
spraying  on  the  caterpillars  was  noticed.  Occasionally  in 
badly  infested  places  so  many  of  the  caterpillars  died  within 
two  or  three  days  after  the  spraying  that  the  people  living 
on  the  infested  estates  were  obliged  for  the  sake  of  cleanliness 
to  sweep  up  the  dead  from  the  walks  and  burn  them.  The 
unevenness  in  the  effect  of  the  spraying  at  once  aroused 
suspicion  that  it  might  be  caused  by  improper  mixing  or 
application  of  the  insecticide.  Although  some  inefficiency 
on  the  part  of  inexperienced  sprayers  was  expected,  a  great 
difference  in  the  effect  of  the  insecticide  was  observed  even 
when  the  poison  was  most  thoroughly  and  carefully  mixed 
and  uniformly  applied. 

Every  effort  was  made  during  the  spraying  season  to  de- 
termine why  the  results  of  spraying  were  not  uniform  and 
satisfactory.  The  feeding  caterpillars  were  watched  day  and 
night  by  many  observers.  The  spraying  was  most  carefully 
superintended  and  the  conclusion  finally  arrived  at  was  that 
under  ordinary  conditions  spraying  with  Paris  green  for  the 
gypsy  moth  was  ineffective  and  unsatisfactory.* 

*  In  a  few  cases,  where  spraying  was  done  just  after  a  storm,  an  unusual  mortality 
among  the  caterpillars  was  noticed  during  the  next  few  days.  At  first  it  was  thought 
that  this  result  was  due  to  the  poison  being  more  effective  at  such  times,  on  account 
of  its  better  retention  on  the  foliage.  It  was  known,  also,  that  the  caterpillars  sought 
shelter  and  ate  but  little  during  rains,  but  that  they  fed  ravenously  during  the  warm, 
clear  weather  that  frequently  follows  a  storm.  It  was  believed  that  the  unusual 
amount  of  poisoned  food  taken  at  such  a  time,  when  the  system  was  weakened  by 
fasting,  might  have  been  sufficient  to  cause  a  greater  mortality  than  usual.  It  was 
soon  noted  that  the  poison  appeared  to  produce  the  same  effect  occasionally  in  dry 
weather  or  after  light  rains.  This  seemed  to  disprove  the  first  hypothesis  advanced, 
and  raised  the  question  whether  the  larvae,  which  sometimes  succumbed  in  such 
numbers,  were  not  first  weakened  by  disease  or  other  causes. 

In  some  cases  the  accuracy  of  the  observations  was  doubted.  It  is  difficult  to  make 
accurate  observations  on  the  results  of  such  work  done  in  the  field.  For  instance, 
it  is  almost  impossible  to  determine  the  proportion  of  larvae  killed  by  spraying. 
When  they  disappear  immediately  after  spraying,  there  is  no  certainty  as  to  whether 
the  spraying  alone  is  responsible  for  their  disappearance,  or  whether  they  have  not 
been  carried  off  by  birds  or  predaceous  insects,  or  have  not  crawled  to  other  localities 
or  to  more  congenial  food.  In  some  places,  where  the  dead  larvae  fell  to  the  ground 
in  considerable  numbers,  most  of  them  were  immediately  carried  away  by  ants  or 
other  scavengers,  which  left  few  behind  to  tell  of  the  results  of  the  spraying.  Cor- 
rect conclusions  cannot  be  drawn  where  there  is  such  liability  of  error,  unless  obser- 
vations recorded  by  many  careful  individuals  and  extending  over  a  considerable 
period  of  time  agree  in  the  main.  As  no  extended  spraying  with  Paris  green  was 
done  after  1891,  the  opportunity  passed  for  an  exhaustive  study  of  the  effect  of 
meteorological  or  other  conditions  on  the  results  of  spraying.  The  cause  of  the 
apparent  differences  in  the  results  of  carefully  conducted  spraying  with  Paris  green 
for  the  gypsy  moth  is  a  question  which  deserves  further  investigation. 


140  THE   GYPSY  MOTH. 

It  is  interesting  to  note  that  while  many  of  the  gypsy 
caterpillars  were  apparently  uninjured  by  the  spraying,  the 
canker-worms  and  tent  caterpillars  were  almost  exterminated, 
and  the  tussock  moths  (Orgyia  leucostigmd}  disappeared. 
The  trees  of  the  infested  region  were  never  in  better  con- 
dition than  at  the  end  of  the  spraying  season  of  1891,  and 
the  fruit  crop  was  larger  than  it  had  been  for  many  years. 
Though  this  cannot  all  be  credited  to  the  spraying,  the  con- 
trast between  sprayed  and  unsprayed  trees  was  often  very 
marked,  the  sprayed  trees  bearing  more  and  finer  fruit. 

During  the  spraying  season  thirty  heavy  spraying  outfits 
were  worked  back  and  forth  between  the  outer  part  of  the 
infested  region  and  its  centre.  Fifteen  towns  were  thus 
covered.  There  were  also  a  dozen  light  fifteen-gallon  hand 
tanks  which  were  sent  into  the  outer  towns.  They  were 
carried  in  wagons,  two  men  being  assigned  to  each  wagon. 
The  tanks  and  pumps  used  were  the  same  as  are  used  with 
the  cyclone  burner  (Fig.  1,  page  120).  The  men  with  the 
light  outfits  went  to  the  outlying  orchards  and  residences, 
where  a  few  trees  were  infested.  They  filled  their  tanks  at 
brooks  or  wells  and  carried  them  by  hand  to  such  infested 
spots  as  were  not  accessible  by  a  team,  sprayed  the  trees  in  the 
vicinity,  reloaded  the  tanks  upon  the  wagons  and  drove  to  the 
next  infested  place.  In  this  way  the  isolated  colonies  in  the 
outer  towns  were  covered  by  the  sprayers.  The  large  tanks 
mounted  upon  wagons  and  handled  by  from  four  to  six  men 
were  used  mainly  in  towns  where  water  service  was  available 
and  were  filled  from  hydrants  or  stand-pipes.  The  order  was 
given  to  spray  everything  green  within  two  hundred  feet  of  an 
infested  plant  or  tree.  An  adherence  to  this  regulation  caused 
the  spraying  of  all  vegetation  in  the  worst  infested  towns. 

No  extended  spraying  with  Paris  green  has  been  done  since 
1891.  While  spraying  with  Paris  green  cannot  be  considered 
a  successful  method  of  extermination,  it  destroyed  a  consid- 
erable proportion  of  the  number  of  very  young  caterpillars 
wherever  it  was  done  efficiently  and  in  season.  It  thus 
checked  the  multiplication  and  assisted  in  preventing  the 
spreading  of  the  species.  Though  it  failed  to  accomplish 
the  end  sought,  it  was  certainly  the  most  effectual  method 
known  at  that  time  of  disposing  of  the  young  caterpillars. 


LONDON  PURPLE.  141 

In  looking  back  over  an  experience  of  five  years  we  are 
unable  to  see  how  any  better  method  of  destroying  the  young 
larvae  could  have  been  devised  from  the  knowledge  of  in- 
secticides then  possessed. 

Spraying  with  London  Purple. 

London  purple  was  used  both  in-doors  and  in  the  field  in 
the  season  of  1891  but  the  results  of  the  experiments  with  it 
were  not  as  satisfactory  as  those  reached  with  Paris  green. 
While  it  was  quite  as  effective  as  Paris  green  in  destroying 
larvae,  it  injured  the  foliage  more.  London  purple  is  more 
finely  powdered  and  lighter  than  Paris  green  and  requires 
less  stirring.  It  also  has  the  advantage  of  cheapness.  The 
great  objections  to  its  use  are  its  partial  solubility  in  water, 
which  causes  burning  of  the  leaves,  and  the  unevenness  of 
the  effects  produced  by  it.  While  one  sample  may  give  fairly 
satisfactory  results,  the  next  may  not  only  burn  the  foliage 
badly  but  even  the  young  fruit  on  fruit  trees.  According  to 
Professor  Bailey  the  arsenic  in  London  purple  is  in  the  form 
of  arsenite  of  calcium,  which  in  some  samples  is  about  seventy- 
two  per  cent,  of  the  whole  compound.  Over  fifty  per  cent,  of 
this  arsenite  or  nearly  forty  per  cent,  of  the  London  purple  is 
quickly  soluble  in  water.*  The  analysis  of  leaves  injured  by 
Paris  green  shows  no  arsenic  in  the  texture  of  the  leaf;  but 
when  leaves  injured  by  London  purple  are  analyzed,  arsenic 
is  found  in  their  texture.  This  shows  the  penetrative  powers 
of  the  latter  poison.  The  London  purple  was  used  in  the 
field  to  some  extent,  but  the  conclusion  arrived  at  was  that 
while,  as  it  is  ordinarily  used,  one  might  be  justified  in  ex- 
perimenting with  it  upon  his  own  premises,  its  use  in  public 
work  on  the  premises  of  others  was  unwarrantable. 

Spraying  with  Arsenate  of  Lead. 

Although  nearly  all  poisons  known  to  us  which  can  be 
used  as  insecticides  have  been  experimented  with  during  the 
past  five  years  in  the  hope  that  something  would  be  found 
which  would  prove  fatal  to  the  gypsy  moth,  only  one  which 
is  more  effective  than  Paris  green  has  been  discovered.  This 

*  See  "Experiences  in  Spraying  Plants"  by  Prof.  L.  H.  Bailey,  Report  Agrieultnral 
Experiment  Station,  Ithaca,  N.  Y.,  Bulletin  18,  1890,  page  98. 


142  THE   GYPSY  MOTH. 

is  arsenate  of  lead,  a  poison  slower  in  its  action  than  the 
other,  but  which  has  three  distinct  advantages:  (1)  It  can 
be  used  at  any  desired  strength  without  serious  injury  to 
the  foliage;  (2)  It  is  visible  wherever  used,  as  it  forms 
a  whitish  coating  on  the  leaves ;  (3)  It  has  adhesive  quali- 
ties, given  it,  probably,  by  the  acetate  of  lead,  and  therefore 
remains  on  the  leaves  for  a  much  longer  period  than  Paris 
green.  When  sufficient  glucose  was  added  to  a  strong  mixt- 
ure of  arsenate  of  lead,  it  withstood  rainstorms  and  remained 
on  the  foliage  during  an  entire  season. 

When  in  1891  it  became  evident  that  the  arsenites  would 
not  accomplish  the  desired  result,  other  means  of  destroying 
dispar  were  sought.  Yet  it  could  be  hardly  credited  that 
the  larva  was  indifferent  to  the  action  of  arsenical  poisons  as 
ordinarily  used,  and  the  experiments  of  1891  were  duplicated 
during  the  season  of  1892.  They  were  performed  by  Pro- 
fessor Fernald  and  his  assistants,  but  the  results  of  these 
experiments  confirmed  those  of  1891. 

When  it  was  seen  that  the  known  arsenites  could  not  be 
used  at  the  requisite  strength  for  killing  gypsy-moth  cater- 
pillars without  serious  injury  to  the  foliage,  Mr.  F.  C. 
Moulton,  one  of  the  inspectors  employed  in  the  field,  who 
was  also  a  chemist  graduated  from  the  State  College  of  Agri- 
culture and  Mechanic  Arts,  Orono,  Me.,  was  detailed  to  make 
experiments  to  determine  what  portion  of  the  compound 
produced  the  caustic  effect  upon  the  foliage.  The  results 
of  the  experiments  confirmed  the  conclusions  of  previous 
experimenters  that  the  soluble  arsenic  burned  the  foliage.  It 
was  obvious  that  if  a  form  of  arsenic  entirely  and  quickly 
soluble  in  water  could  be  precipitated,  it  would  become 
insoluble  and  obviate  the  burning. 

In  the  winter  of  1892-93,  at  a  hearing  before  the  legis- 
lative joint  standing  committee  on  agriculture,  a  bill  for  the 
destruction  of  caterpillars  within  the  State  was  considered. 
At  this  hearing  Mr.  Andrew  H.  Ward  proposed  the  use  of 
arsenate  of  soda  as  an  insecticide.  At  the  hearing  we  ob- 
tained from  Mr.  Ward  the  particulars  in  regard  to  the  price 
of  arsenate  of  soda  and  where  it  could  be  procured. 

Upon  consultation  with  Professor  Fernald  (who  had  also 
been  previously  asked  by  Mr.  Ward  to  try  the  insecticide 


ARSENATE   OF  LEAD.  143 

properties  of  arsenate  of  soda),  he  advised  experimenting 
with  it.  A  sample  was  procured  and  was  found  to  be  entirely 
soluble  in  water.  When  used  it  burned  the  foliage  to  a 
greater  extent  than  the  other  arsenical  poisons.  Mr.  Moul- 
ton  was  detailed  to  find  some  material  which  would  precipi- 
tate the  arsenate  of  soda  in  water  and  thus  obviate  the 
burning.  He  proposed  acetate  of  lead  and  after  several 
experiments  the  desired  result  was  obtained  and  the  pro- 
portions were  fixed.  The  effect  of  the  mixture  of  acetate 
of  lead  with  arsenate  of  soda  in  water  is  to  throw  down  the 
arsenate  of  lead  in  a  fine  precipitate  which  is  held  well  in 
suspension  by  the  water  and  is  therefore  more  evenly  dis- 
tributed than  Paris  green. 

While  the  complete  insolubility  of  arsenate  of  lead  is  an 
advantage  as  far  as  its  effects  on  the  plants  are  concerned, 
it  is  less  effective  on  the  insect  than  Paris  green  when  used 
in  equal  quantities.  Though  the  action  of  arsenate  of  lead 
is  slower  than  that  of  Paris  green  and  London  purple,  this 
may  be  partially  accounted  for  by  the  smaller  proportion 
of  arsenic  in  the  composition.  Caterpillars  poisoned  with 
arsenate  of  lead  have  quite  a  different  appearance  from  those 
poisoned  with  Paris  green.  Inflammation  and  the  shedding 
of  hair  appear  to  be  symptoms  of  poisoning  by  arsenate  of 
lead.  As  it  is  slow  in  its  action,  it  is  well  to  apply  it  early 
in  the  life  of  the  caterpillar  or  in  great  strength. 

The  experience  with  arsenate  of  lead  is  in  some  respects 
analogous  to  that  with  Paris  green.  While  in-doors  there  is 
no  difficulty  in  destroying  caterpillars  with  small  quantities 
of  the  poison,  the  effects  obtained  out-doors  are  not  so  satis- 
factory. Indeed,  it  is  only  when  applied  at  a  strength  of  from 
twenty-five  to  thirty  pounds  to  one  hundred  and  fifty  gallons 
of  water  that  it  appears  to  do  exterminative  work.  This,  to 
some  extent,  may  be  due  to  the  difference  in  the  material. 
The  arsenate  of  lead  used  in  the  laboratory  was  furnished  in 
the  form  of  a  fine  dry  precipitate.  In  the  field  the  two 
poisons  were  furnished  in  a  cruder  state.  They  were  added 
to  the  water  and  precipitation  took  place  in  the  tank.  The 
preparation '  was  much  less  expensive  when  made  in  this 
way  but  was  not  as  finely  powdered.  Indeed,  it  required 
considerable  stirring  in  warm  or  hot  water  to  dissolve  the 


144  THE   GYPSY  MOTH. 

lead  sufficiently  for  it  to  pass  through  the  strainers  of  the 
pump.  When  arsenate  of  lead  has  been  applied  in  pro- 
portions of  from  twenty-five  to  thirty  pounds  to  one  hun- 
dred and  fifty  gallons  of  water,  occasional  burning  has  been 
noticed.  This  was  due  to  the  fact  that  the  lead  was  not 
thoroughly  dissolved,  for  in  such  cases  there  was  a  lack 
instead  of  an  excess  of  acetate  of  lead  in  the  mixture  as  it 
came  from  the  nozzle.  When  applied  in  this  strength  it 
is  a  question  whether  it  is  safe  to  use  it  in  pastures  where 
cattle  are  feeding  or  near  where  poultry  are  quartered. 

It  is  evident  that  spraying  with  arsenate  of  lead  should  be 
used  as  an  exterminative  method  only  in  exceptional  cases 
where  there  is  no  danger  to  animals  and  where  more  drastic 
measures,  such  as  fire,  cannot  be  used.  While  it  will  un- 
doubtedly be  useful  with  many  other  insects,  we  would  not 
recommend  that  implicit  reliance  be  placed  upon  it  unless 
used  early  in  the  season  and  at  a  strength  of  at  least  three 
pounds  to  one  hundred  and  fifty  gallons  of  water.  However, 
it  will  probably  not  be  necessary  to  use  it  at  this  strength 
for  all  leaf-eating  insects  though  some  may  require  a  greater 
strength.  Many  experimenters  have  made  trials  of  this  ma- 
terial since  the  formula  was  first  published  in  the  annual 
report  of  the  State  Board  of  Agriculture  in  1894,  but  we 
are  not  aware  that  it  has  yet  come  into  general  use  in  practi- 
cal out-door  work.  Professor  Fernald's  experiments  with 
arsenate  of  lead  on  the  tent  caterpillar  indicate  that  it  would 
be  effective  with  this  species  in  the  field  when  used  at  a 
strength  of  one  pound  to  one  hundred  and  fifty  gallons  of 
water.  It  has  given  good  results  when  used  by  him  at  the 
same  strength  for  the  Colorado  potato  beetle  (Doryphora 
decemlineata,  Say) .  Larger  quantities  have  been  required  for 
some  other  insects. 

At  first  sight  it  would  seem  that  if  it  were  necessary  to  use 
three  pounds  of  arsenate  of  lead  to  one  hundred  and  fifty 
gallons  of  water,  the  expense  would  be  prohibitory.  Yet  it 
should  be  borne  in  mind  that  when  mixed  with  glucose  and 
properly  applied  to  dry  foliage,  much  of  the  solution  will 
remain  throughout  most,  or  all,  of  the  feeding  season.  Its 
application  is  not,  therefore,  as  expensive  as  that  of  poisons 
which  have  to  be  applied  three  or  more  times  during  the  season. 


SPRAYING  APPARATUS. 


145 


By  making  a  strong  application  early,  the  expense  of  the 
labor  of  making  the  later  applications  is  done  away  with. 
Experiments  being  made  by  entomologists  in  different  parts 
of  the  country  will  soon  indicate  the  degree  of  usefulness 
of  this  arsenate  in  destroying  different  species  of  native  and 
introduced  leaf-eating  insects.  Practical  use  in  the  field 
later  will  determine  its  value  as  a  general  insecticide. 

In  the  field  work  of  the  Board  of  Agriculture  the  formula 
of  arsenate  of  lead  most  used  was  sodic  arsenate,  29.93  per 
cent.,  plumbic  acetate,  70.07  per  cent.  Two  quarts  of  glu- 
cose were  generally  added  to  150  gallons  of  water  to  give 
better  adhesive  qualities. 

Professor  Fernald  directs  that  arsenate  of  lead  can  be 
prepared  in  the  proportion  of  eleven  ounces  of  acetate  of  lead 
and  four  ounces  of  arsenate  of  soda  in  water. 

Apparatus  used  for  Spraying  Large  Shade  and  Forest  Trees. 


FIG.  9.    Spraying  tank. 


The  heavy  spraying  outfits  used  by  the  first  commission 
in  1890  were  again  put  in  service  by  the  State  Board  of 


146  THE   GYPSY  MOTH. 

Agriculture  in  1891,  but  were  so  improved  and  modified  by 
labor-saving  attachments  as  to  render  them  doubly  effective. 
For  each  of  these  outfits  a  tank  or  hogshead  holding  one 
hundred  and  sixty  gallons  (Fig.  9)  is  provided,  bearing  on 
its  upper  end  a  plank  foot-board  six  feet  long  and  one  foot 
wide.  A  double-acting  Douglass  or  Gould  force-pump  (see 
Plate  XXV.,  Fig.  1,  and  Plate  XXVI.,  Fig.  2)  is  mounted 
near  the  middle  of  the  foot-board.  Either  of  these  pumps 
when  well  manned  furnishes  sufficient  force  for  all  kinds  of 
spraying  with  several  nozzles  at  once.  The  suction  pipe  of 
the  pump  descends  into  the  tank  at  the  side  and  reaches  to 
within  two  inches  of  the  bottom,  where  it  is  terminated  by  a 
fine  wire  gauze  strainer  made  from  No.  32  wire,  woven  forty 
or  fifty  meshes  to  the  inch,  which  serves  to  exclude  all  foreign 
substances  which  may  clog  the  pump  or  nozzle.  The  diame- 
ter of  the  strainer  should  not  be  less  than  twice  that  of  the 
suction  pipe.  In  the  head  of  the  tank  is  inserted  a  stirrer 
made  from  two  pieces  of  two-inch  spruce  scantling,  one  six 
feet  and  the  other  two  feet  in  length,  the  two  being  joined  at 
right  angles  at  the  lower  end  of  the  longer  piece.  When 
placed  in  the  tank  the  long  arm  is  hinged  on  a  bolt  or  rod 
at  the  opening  in  the  head  of  the  hogshead  while  the  short 
arm  swings  just  clear  of  the  bottom.  This  lever  projects 
above  the  top  of  the  tank.  By  moving  it  back  and  forth 
the  liquid  is  thoroughly  agitated.  The  pump  is  operated 
by  means  of  a  powerful  lever  or  brake  worked  by  one  or 
two  men,  according  to  the  amount  of  pressure  needed.  It 
is  connected  by  means  of  a  Y  coupling  with  two  lines  of  hose 
upon  which  from  two  to  six  nozzles  can  be  used.  The  men 
when  pumping  stand  on  the  foot-board  already  mentioned. 
The  whole  apparatus  is  lashed  on  a  wagon  or  cart  and  trans- 
ported from  place  to  place  as  required.  When  in  use  one 
man  operates  each  line  of  hose,  the  driver  of  the  team  usu- 
ally does  the  stirring,  while  the  whole  work  of  spraying 
is  directed  by  an  inspector.  With  this  apparatus  there  is 
no  difficulty  in  spraying  at  any  required  height.  Two 
men  on  the  brakes  furnish  force  sufficient  to  throw  a  good 
spray  from  a  Gem  nozzle  when  held  ninety  feet  from  the 
ground. 


SPRAYING  APPARATUS.  147 

Thorough  and  constant  stirring  is  the  prime  requisite  for 
obtaining  satisfactory  and  uniform  results  in  spraying,  as 
the  arsenical  compounds  used  do  not  enter  into  true  solution 
with  water,  but  having  greater  specific  gravity  remain  in  sus- 
pension only.  For  this  reason  the  particles  of  the  poison 
have  a  constant  tendency  to  settle  to  the  bottom  of  the  tank. 
Therefore  the  strength  of  the  solution  varies  according  to 
the  amount  of  agitation  given  it.  Hence  the  necessity  of 
a  continuous  stirring  of  the  contents  of  the  spraying  tank 
even  when  the  pump  is  not  being  used,  as  while  it  is 
being  taken  from  one  tree  to  another.  Even  with  con- 
tinuous stirring  the  liquid  issuing  from  the  nozzle  when 
the  tank  was  nearly  emptied  usually  contained  more  poison 
than  that  taken  from  a  full  tank  or  one  half  full.  In  most 
spraying  machines  the  liquid  is  agitated  only  when  the  pump 
is  in  motion  and  the  insecticide  settles  when  the  pump  is 
not  in  use.  It  then  becomes  necessary  to  scrape  the  bottom 
of  the  tank  and  stir  vigorously. 

Several  kinds  of  hose  were  used  in  spraying.  The  half- 
inch,  rubber-lined,  cotton-covered  Eureka  ho»e  was  found  to 
be  most  convenient  for  the  heavy  apparatus  on  account  of 
its  light  weight.  For  light  machines,  where  only  one  small 
nozzle  is  used  to  each  line  of  hose,  quarter-inch  rubber  tub- 
ing is  large  enough.  Each  spraying  gang  was  supplied  with 
eight  pieces  of  hose,  each  fifty  feet  in  length,  which  were 
used  in  two  lines  of  two  hundred  feet  each.  These  were 
sometimes  united  to  form  a  single  line  so  as  to  spray  places 
which,  from  their  locality,  could  not  be  reached  otherwise. 
In  general  use,  however,  the  two  lines  of  hose  were  used 
simultaneously.  A  "  shut  off"  was  coupled  on  each  line  of 
hose  near  the  pump  and  also  at  the  nozzle. 

Not  the  least  important  part  of  the  spraying  apparatus  is 
the  nozzle.  The  desirable  qualities  of  a  nozzle  for  spraying 
large  trees  are  that  it  shall  throw  voluminous  jets  of  spray 
to  a  distance  of  eight  or  ten  feet,  clear  itself  readily,  and 
be  easily  adjusted  to  varying  distances,  thus  enabling  the 
workmen  to  work  rapidly.  A  series  of  tests  was  made  with 
thirty-three  different  kinds  of  nozzles.  The  Lowell  and  Gem 
nozzles  were  found  to  be  most  effective.  Both  of  these  noz- 


148  THE  GYPSY  MOTH. 

zles  are  operated  on  the  same  principle  and  both  have  been 
much  used  in  the  gypsy-moth  work.  A  good  climber  us- 
ing the  Gem  nozzle  can  spray  large  trees  both  thoroughly  and 
rapidly. 

When  it  is  impossible  to  reach  the  ends  of  branches  with 
a  fine  spray,  a  turn  of  the  nozzle  will  cause  a  heavier  spray 
to  be  thrown  to  a  distance  of  ten  or  twelve  feet.  If  neces- 
sity requires,  this  can  be  reduced  to  a  stream  which  can  be 
forced  upward  for  thirty  feet,  where  it  will  break  into  drops ; 
but  when  the  foliage  can  be  reached  with  a  spray,  the  use 
of  the  stream  should  not  be  permitted,  as  such  work  does 
not  give  the  best  results. 

There  are  some  objections  to  the  use  of  these  nozzles.  They 
waste  more  or  less  of  the  liquid  and  do  not  distribute  it  so 
finely  as1  some  other  nozzles.  They  also  may  tempt  the 
workman  to  avoid  climbing  by  substituting  the  stream  for  the 
spray  where  the  branches  are  not  easily  accessible,  thus  im- 
pairing the  efficiency  of  the  spraying.  Yet  if  the  operations 
are  superintended  by  competent  men,  this  may  be  guarded 
against  and  the  work  done  far  more  rapidly  than  with  non- 
adjustable  nozzles  throwing  a  finer  spray. 

The  Lowell  nozzle  (Plate  XXIV.,  Fig.  2)  consists  essen- 
tially of  two  brass  tubes  placed  one  within  the  other.  The 
inner  tube  at  its  posterior  end  bears  a  coupling  by  means  of 
which  it  is  connected  with  the  hose,  while  the  anterior  end 
terminates  in  a  tapering  point  at  the  base  of  which  on  op- 
posite sides  are  two  openings  which  allow  the  fluid  to  escape 
into  the  chamber  between  the  tubes.  The  cone-shaped  point 
of  the  inner  tube  tapers  for  about  two-thirds  of  its  length,  at 
which  point  its  diameter  is  abruptly  enlarged  and  then  tapers 
again  at  an  increased  angle  to  its  apex.  On  the  outside  of  the 
inner  tube  is  a  coarse  screw  thread  which  moves  on  a  blunt 
screw  inserted  through  the  side  of  the  outer  tube  and  by 
this  arrangement  the  latter  is  moved  forward  and  backward. 
This  outer  tube,  which  is  slightly  shorter  than  the  inner  one, 
closes  on  the  latter  at  the  posterior  end  by  means  of  a  band 
of  packing  held  in  place  by  a  movable  nut.  At  its  anterior 
end  it  is  widened  to  form  a  bell-shaped  opening  which  at 
the  centre  closes  tightly  around  the  tapering  point  of  the 
inner  tube.  When  in  use  the  outer  tube  is  slid  forward  by 


Plate    XXIV. 


F\g.  2. 


N92 


Fig,  3. 


Fig.  4. 


Plate    XXV. 


Fig.  2. 


Plate    XXVI. 


Fig.  2. 


Plate    XXVII. 


Fig.  I. 


Fig.  2. 


Fig.  5.  Fig.  4. 


Fig.  6. 


SPRAYING  APPARATUS.  149 

a  rotary  motion  on  the  screw  bearing  of  the  inner  tube,  and 
the  spraying  solution  is  forced  out  through  the  circular  space 
thus  opened  between  the  point  of  the  inner  tube  and  the 
inner  surface  of  the  outer  tube,  which  surround  it.  By 
turning  the  outer  tube  the  density  of  the  spray  and  the  dis- 
tance to  which  it  can  be  thrown  are  regulated. 

The  Gem  nozzle  (Plate  XXIV.,  Fig.  4)  is  made  on  the 
same  principle  as  the  Lowell.  In  using  these  nozzles  a  strong 
pressure  is  required  to  insure  a  fine  spray. 

For  spraying  orchard  trees  and  shade  trees  of  ordinary 
size,  light  hand  ladders  were  found  to  be  very  serviceable. 
But  when  the  tops  of  tall  street  elms  were  sprayed,  extension 
ladders,  thirty,  forty  or  even  sixty  feet  in  length,  were  nec- 
essary. A  heavy  extension  ladder  sixty-five  feet  in  length, 
such  as  is  used  by  firemen,  was  purchased  for  the  latter 
purpose.  This  ladder  could  be  readily  and  skilfully  handled 
by  six  men  with  the  aid  of  blocks  and  tackle.  The  small 
hand  ladders  were  carried  on  the  spraying  wagons  and  the 
larger  ones  by  hand  or  upon  wagons,  hand-carts  or  wheels, 
as  was  most  convenient.  Ladders  mounted  permanently 
upon  wheels  could  not  be  used  to  advantage  on  account  of 
the  uneven  nature  of  the  ground  where  much  of  the  spraying 
was  done.  Ladders  twenty  to  twenty-five  feet  in  height  with 
braces  so  made  that  they  could  be  set  up  like  step-ladders 
were  used  at  first,  but  they  were  unwieldy  and  it  was  soon 
seen  that  more  effective  work  could  be  done  by  using  light 
ladders  and  climbing  into  the  trees  themselves.  In  climbing 
fruit  and  shade  trees  care  must  be  taken  not  to  injure  the 
branches. 

Machinery  for  Spraying  Orchard  Trees  and  Garden  Plants. 

Although  in  spraying  small  gardens  and  orchards  any  good 
tank  or  pump  may  be  used,  the  heavy  and  more  cumber- 
some outfits  are  not  necessary.  A  small  portable  tank  and 
pump  which  can  be  taken  about  by  the  operator,  either 
attached  to  his  person  or  upon  a  wheelbarrow,  will  suffice 
for  all  the  spraying  required  in  small  estates. 

For  spraying  garden  plants  and  small  fruit  trees  the 
"  knapsack  pump,"  which  is  fastened  on  the  shoulders, 
has  been  otten  recommended  for  use  in  small  gardens  and 


150  THE   GYPSY  MOTH. 

orchards.  The  Gould  handy  knapsack  spraying  pump 
(Plate  XXIV.,  Fig.  1)  has  been  used  experimentally  in 
the  gypsy-moth  work  and  gives  fairly  good  results.  These 
knapsack  sprayers,  however,  are  inconvenient  when  spraying 
is  required  on  a  large  scale  as  they  do  not  carry  sufficient 
liquid. 

The  hand  tank  and  pump  used  with  the  cyclone  burner 
(page  120,  Fig.  1)  has  been  found  very  useful  in  spraying 
small  orchards.  With  the  pole  attachment  most  of  the  trees 
can  be  sprayed  from  the  ground.  This  tank  may  be  carried 
and  operated  by  two  men. 

Gould's  barrel  sprayer  is  shown  in  Plate  XXV.,  Fig.  2. 
It  has  been  very  useful  in  our  experimental  work,  and  could 
no  doubt  be  used  to  advantage  in  spraying  small  orchards, 
gardens  and  field  crops.  It  has  the  advantage  of  being 
movable  without  the  aid  of  a  horse.  Its  wide  tires  can  be 
run  over  ground  where  it  would  not  be  possible  for  a  horse 
to  go  without  doing  injury. 

In  spraying  in  gardens  where  tender  and  valuable  plants 
are  grown  or  in  orchards  containing  choice  varieties  of  fruit 
trees,  it  is  most  essential  that  the  liquid  be  thoroughly 
stirred,  and  especially  that  the  spray  be  distributed  evenly 
and  in  a  fine  mist,  otherwise  injury  to  the  plant  may  result. 
Spraying  may  be  done  with  the  crudest  implements.  Corn- 
brooms  and  whitewash  brushes  have  been  used  with  good 
effect  in  some  cases,  but  for  uniformly  good  results  we  have 
seen  nothing  better  than  some  of  the  modifications  of  the 
cyclone  nozzle  (Plate  XXVII.,  Fig.  2).  This  nozzle  was 
originally  brought  to  public  notice  by  Professor  Riley,  then 
chief  of  the  United  States  Entomological  Commission.  When 
used  in  its  original  form,  it  throws  a  finer  and  more  even 
spray  than  any  nozzle  which  has  come  to  our  notice,  yet  it 
has  faults  which  preclude  its  use  except  in  very  limited 
fields.  It  sprays  very  slowly  and  is  frequently  clogged  by 
the  coarser  particles  of  the  insecticide  or  by  foreign  sub- 
stances, the  perforation  through  which  the  liquid  passes  out 
in  spray  being  very  small.  It  is  then  necessary  to  remove 
the  cap  and  clear  the  nozzle!  Therefore  much  time  is  con- 
sumed in  its  use.  When  first  tried  experimentally  at 
Medford  it  was  found  that  an  hour  was  required  to  spray 


SPRAYING  APPARATUS.  151 

thoroughly  a  large  apple  tree.  Still  the  cyclone  nozzle  has 
been  used  to  some  advantage  against  the  gypsy  moth  by 
uniting  four  nozzles  in  one  (Fig. 
10)  and  slightly  enlarging  their  aper- 
tures. The  nozzles  radiate  some- 
what so  that  the  spray  from  the 
four  covers  a  much  larger  field  than 
that  from  only  one.  The  amount 
of  the  spray  thrown  in  a  given 
time,  as  well  as  the  area  of  the 
foliage  covered,  is  more  than  quad- 
rupled. Yet  clogging  occurs  more  Fl 
frequently  on  account  of  the  greater  number  of  nozzles. 

The  Vermorel  modification  of  the  cyclone  nozzle  (Plate 
XX1IL,  Fig.  1)  is  an  improvement  on  the  original  inven- 
tion. It  throws  more  liquid  than  the  cyclone  but  gives  a 
fine,  even  spray  which,  because  of  its  fineness,  cannot  be 
projected  to  a  distance.  This  spray  will  drift  on  the  wind, 
however,  so  that  spraying  can  be  done  for  some  distance  to 
the  leeward  of  the  operator.  Though  this  nozzle  uses  less 
of  the  spraying  fluid  than  the  Gem  or  Lowell  nozzles,  it 
uses  more  than  the  cyclone  and  therefore  will  spray  more 
rapidly  than  the  latter.  It  distributes  the  spray  more  finely 
and  evenly  than  the  Gem  or  Lowell  nozzles  and  gives  better 
satisfaction  in  spraying  small  trees  or  shrubbery.  Experi- 
ments indicate  that  in  the  number  of  caterpillars  killed,  there 
is  a  slight  difference  in  favor  of  the 
Vermorel  nozzle  over  the  nozzles 
previously  mentioned.  Spraying 
may  be  done  more  rapidly  by  at- 
taching two  or  more  nozzles  to  the 
same  hose  by  means  of  the  Y  coup- 
ling (Fig.  11). 

The  Vermorel  nozzle  consists  of 
a  short  brass  tube  bent  at  right 
angles,  having  a  coupling  at  one 
end  by  means  of  which  it  is  at- 

FIG.  11.    Y  nozzle. 

tached  to  the  hose  and  at  the  other 

end  entering  at  right  angles  a  small  cylinder,  which  is  divided 

by  a  transverse  partition  into  two  chambers. 


150  THE   GYPSY  MOTH. 

orchards.  The  Gould  handy  knapsack  spraying  pump 
(Plate  XXIV.,  Fig.  1)  has  been  used  experimentally  in 
the  gypsy-moth  work  and  gives  fairly  good  results.  These 
knapsack  sprayers,  however,  are  inconvenient  when  spraying 
is  required  on  a  large  scale  as  they  do  not  carry  sufficient 
liquid. 

The  hand  tank  and  pump  used  with  the  cyclone  burner 
(page  120,  Fig.  1)  has  been  found  very  useful  in  spraying 
small  orchards.  With  the  pole  attachment  most  of  the  trees 
can  be  sprayed  from  the  ground.  This  tank  may  be  carried 
and  operated  by  two  men. 

Gould's  barrel  sprayer  is  shown  in  Plate  XXV.,  Fig.  2. 
It  has  been  very  useful  in  our  experimental  work,  and  could 
no  doubt  be  used  to  advantage  in  spraying  small  orchards, 
gardens  and  field  crops.  It  has  the  advantage  of  being 
movable  without  the  aid  of  a  horse.  Its  wide  tires  can  be 
run  over  ground  where  it  would  not  be  possible  for  a  horse 
to  go  without  doing  injury. 

In  spraying  in  gardens  where  tender  and  valuable  plants 
are  grown  or  in  orchards  containing  choice  varieties  of  fruit 
trees,  it  is  most  essential  that  the  liquid  be  thoroughly 
stirred,  and  especially  that  the  spray  be  distributed  evenly 
and  in  a  fine  mist,  otherwise  injury  to  the  plant  may  result. 
Spraying  may  be  done  with  the  crudest  implements.  Corn- 
brooms  and  whitewash  brushes  have  been  used  with  good 
effect  in  some  cases,  but  for  uniformly  good  results  we  have 
seen  nothing  better  than  some  of  the  modifications  of  the 
cyclone  nozzle  (Plate  XXVII.,  Fig.  2).  This  nozzle  was 
originally  brought  to  public  notice  by  Professor  Riley,  then 
chief  of  the  United  States  Entomological  Commission.  When 
used  in  its  original  form,  it  throws  a  finer  and  more  even 
spray  than  any  nozzle  which  has  come  to  our  notice,  yet  it 
has  faults  which  preclude  its  use  except  in  very  limited 
fields.  It  sprays  very  slowly  and  is  frequently  clogged  by 
the  coarser  particles  of  the  insecticide  or  by  foreign  sub- 
stances, the  perforation  through  which  the  liquid  passes  out 
in  spray  being  very  small.  It  is  then  necessary  to  remove 
the  cap  and  clear  the  nozzle:  Therefore  much  time  is  con- 
sumed in  its  use.  When  first  tried  experimentally  at 
Medford  it  was  found  that  an  hour  was  required  to  spray 


SPRAYING  APPARATUS.  151 

thoroughly  a  large  apple  tree.  Still  the  cyclone  nozzle  has 
been  used  to  some  advantage  against  the  gypsy  moth  by 
uniting  four  nozzles  in  one  (Fig. 
10)  and  slightly  enlarging  their  aper- 
tures. The  nozzles  radiate  some- 
what so  that  the  spray  from  the 
four  covers  a  much  larger  field  than 
that  from  only  one.  The  amount 
of  the  spray  thrown  in  a  given 
time,  as  well  as  the  area  of  the 
foliage  covered,  is  more  than  quad- 

i    j         AT   j.      i          •  FlG- 10-   Quadruple  cyclone  nozzle. 

rupled.     Yet  clogging  occurs  more 

frequently  on  account  of  the  greater  number  of  nozzles. 

The  Vermorel  modification  of  the  cyclone  nozzle  (Plate 
XX1IL,  Fig.  1)  is  an  improvement  on  the  original  inven- 
tion. It  throws  more  liquid  than  the  cyclone  but  gives  a 
fine,  even  spray  which,  because  of  its  fineness,  cannot  be 
projected  to  a  distance.  This  spray  will  drift  on  the  wind, 
however,  so  that  spraying  can  be  done  for  some  distance  to 
the  leeward  of  the  operator.  Though  this  nozzle  uses  less 
of  the  spraying  fluid  than  the  Gem  or  Lowell  nozzles,  it 
uses  more  than  the  cyclone  and  therefore  will  spray  more 
rapidly  than  the  latter.  It  distributes  the  spray  more  finely 
and  evenly  than  the  Gem  or  Lowell  nozzles  and  gives  better 
satisfaction  in  spraying  small  trees  or  shrubbery.  Experi- 
ments indicate  that  in  the  number  of  caterpillars  killed,  there 
is  a  slight  difference  in  favor  of  the 
Vermorel  nozzle  over  the  nozzles 
previously  mentioned.  Spraying 
may  be  done  more  rapidly  by  at- 
taching two  or  more  nozzles  to  the 
same  hose  by  means  of  the  Y  coup- 
ling (Fig.  11). 

The  Vermorel  nozzle  consists  of 
a  short  brass  tube  bent  at  right 
angles,  having  a  coupling  at  one 
end  by  means  of  which  it  is  at- 

J  Fio.  11.    T  nozzle. 

tached  to  the  hose  and  at  the  other 

end  entering  at  right  angles  a  small  cylinder,  which  is  divided 

by  a  transverse  partition  into  two  chambers. 


154  THE  GYPSY  MOTH. 

out  climbing.  The  extension  nozzles  ordinarily  made,  being 
but  five  or  six  feet  in  length,  are  not  particularly  useful  for 
this  purpose,  but  may  be  used  to  advantage  when  the  work- 
man stands  on  a  tirm  step-ladder.  In  the  work  on  the  gypsy 
moth  a  light  wooden  pole  twelve  feet  in  length  was  used 
in  orchard  spraying.  The  nozzle  and  hose  were  attached 
to  this  pole  by  means  of  snap  hooks,  or  the  nozzle  was 
secured  to  the  end  of  the  pole  by  means  of  a  cap  provided 
for  the  purpose.  In  using  this  pole  the  workman  carried 
the  lower  end  in  a  socket  attached  to  a  belt  around  the 
waist. 


Power  Spraying  Machines  for  Orchards  and  Field  Crops. 

Several  horse-power  spraying  machines  have  been  pro- 
duced with  the  intent  of  saving  time,  labor  and  money  to 
the  user.  In  using  such  of  these  machines  as  we  have  seen, 
it  is  necessary  to  keep  the  horse  moving  in  order  to  work 
the  pump  by  horse  power,  and  it  is  difficult  to  get  sufficient 
power  without  driving  too  fast  to  give  time  for  thoroughly 
spraying  the  trees  in  passing.  Therefore  in  spraying  trees 
the  pump  must  be  operated  by  hand.  These  machines  are 
valuable  in  spraying  potatoes  and  other  crops  grown  on  the 
ground. 

The  "  giant,  automatic  power  sprayer"  (Plate  XXVI.,  Fig. 
1)  has  been  adopted  for  use  in  the  gypsy-moth  work,  but  as 
yet  has  not  been  thoroughly  tested  in  the  field.  It  consists 
of  a  sixty-gallon  oak  tank  suspended  between  two  wheels 
with  wide  tires.  The  diameter  of  the  wheel  is  three  and 
one-half  feet.  The  frame  is  strongly  made  to  enable  the 
operator  to  use  the  machine  upon  rough  ground.  Endless 
sprocket  gears  attached  to  the  wheels  communicate  the  power 
to  the  handle  of  the  pump  by  means  of  a  shaft.  The  gear- 
ing may  be  thrown  out  of  action  in  an  instant  to  prevent 
waste  when  it  is  not  desired  to  operate  the  sprayer.  The 
pump  can  be  disconnected  from  the  horse-power  machinery 
and  operated  by  hand  in  spraying  large  trees.  This  sprayer 
in  operation  is  shown  in  Plate  XXVIII.  Several  steam 
spraying  machines  have  been  invented,  but  we  have  had 
no  experience  in  their  use. 


SPRAYING  APPARATUS.  155 

The  Care  of  Spraying  Machinery. 

The  operations  of  spraying  are  frequently  more  or  less 
delayed  by  minor  accidents  or  imperfect  working  of  parts 
of  the  machinery.  The  action  of  the  insecticide  mixtures 
corrodes  certain  parts  and  the  pumps  require  constant  at- 
tention to  keep  them  in  good  working  order.  Unless  their 
construction  is  understood  by  either  the  workmen  or  the  man 
in  charge,  considerable  delay  and  loss  of  time  are  occasioned 
by  sending  the  pumps  away  for  repairs  or  awaiting  the 
services  of  experts  called  in  to  remedy  the  difficulty.  Yet 
most  of  the  trouble  may  be  easily  and  quickly  remedied  if 
the  men  using  the  apparatus  have  a  sufficient  knowledge  of 
the  different  parts  of  the  pump  to  take  out  those  that  work 
imperfectly,  repair  and  replace  them.  Most  of  the  delays  in 
the  field  are  caused  by  either  a  clogging  of  the  strainer  in 
the  tank,  some  obstruction  in  the  valves  or  the  wearing 
of  the  packing  of  the  piston  in  the  cylinder. 

Before  the  spraying  apparatus  is  sent  into  the  field  in 
the  spring,  it  should  be  thoroughly  overhauled  and  tested. 
While  the  spraying  is  in  progress,  each  of  the  spraying 
gangs  should  be  furnished  with  a  tool  box  containing 
wrenches,  tools,  packing  and  other  materials  which  are  use- 
ful in  taking  apart  the  pumps  and  making  repairs.  Mr.  E. 
C.  Ware,  who  superintended  the  spraying  teams  in  1891, 
gives  the  following  information  and  directions  in  regard  to 
the  care  of  pumps  in  the  field  :  — 

If  a  pump  fails  to  throw  a  stream,  it  is  well  to  put  some 
clean  water  in  at  the  top,  as  it  is*  quite  often  the  case  that 
the  valves  are  made  or  lined  with  leather,  which,  in  drying, 
has  become  hard  or  warped  out  of  shape.  If  the  pump  is 
an  old  one  and  the  valves  are  of  leather,  it  may  require  new 
valves  before  it  can  be  made  to  work.  If  the  pump  still 
fails  to  operate  satisfactorily,  examine  the  strainer  to  see 
whether  it  has  become  clogged,  as  the  trouble  with  the  pump 
can  be  quite  often  found  at  the  bottom  of  the  strainer.  If  the 
pump  has  not  been  used  for  a  day  or  two,  the  strainer  may 
have  become  corroded.  Sediment  from  the  material  used  for 
spraying  will  sometimes  dry  on  the  meshes  of  the  strainer  so 
as  to  prevent  the  passing  of  the  liquid  through  the  pump. 


156  THE   GYPSY  MOTH. 

When  Paris  green,  lime,  arsenate  of  lead  or  similar  com- 
positions are  used  with  glucose  or  other  adhesive  constituents, 
and  the  pump  is  not  thoroughly  cleaned  after  using,  trouble 
with  the  valves  may  be  expected.  When  the  trouble  cannot  be 
found  at  the  strainer,  it  is  well  to  clean  the  valves  thoroughly, 
being  careful  to  put  them  back  in  their  original  positions, 
seeing  that  the  packing  is  clean  and  in  place  before  putting 
the  screws  back  or  screwing  any  nuts  down.  In  tightening 
the  nuts  or  screws,  put  them  down  until  they  come  to  an 
easy  bearing  all  around  ;  after  which  go  over  them  again  -and 
settle  them  down  tightly.  In  case  the  pump  should  be  a 
heavy  one  having  a  piston  working  through  packing,  and  the 
liquid  escapes  around  the  piston,  loosen  the  large  nut  and 
take  out  the  ring  which  will  be  found  pressed  in  by  the  nut. 
If  the  packing  which  will  probably  be  found  there  is  ha^d 
and  dry,  it  will  be  well  to  replace  it  with  some  hemp  packing 
such  as  is  used  by  steam  fitters  (or  if  this  is  not  at  hand, 
with  cotton  wicking),  saturating  it  with  heavy  oil  or  tallow 
mixed  with  a  liberal  supply  of  black  lead  (graphite).  Soak 
the  packing  thoroughly  and  wind  it  loosety  about  the  piston, 
pushing  it  in  the  mean  time  toward  the  pump  until  you  have 
about  as  much  wound  on  as  the  ring  will  push  in  without 
preventing  the  nut  from  catching.  Then  screw  the  nut  up 
as  far  as  it  will  go  without  preventing  the  pump  from  work- 
ing easily.  It  is  not  well  to  screw  it  up  too  tightly  at  first, 
but  to  turn  it  a  little  at  a  time,  just  enough  to  keep  the 
pump  from  leaking. 

In  connecting  hose  to  Dumps,  it  will  be  found  necessary 
to  use  rubber  washers  at  all  connections  to  prevent  leakage 
when  couplings  are  screwed  together.  Wherever  the  cast- 
ings or  other  parts  of  the  pump  are  broken  by  accident,  much 
time  may  be  saved  if  duplicate  parts  are  kept  ready  for  such 
an  emergency.  Before  the  pumps  are  stored  at  the  end  of 
the  spraying  season,  they  should  be  fa  ken  apart  and  care- 
fully cleaned  and  oiled. 

When  to  Spray  for  the  Gypsy  Moth. 
Spraying  should  be  done  early  in  the  season,  as  soon  as 
the  leaves  are  well  grown,  for  at  that  time  there  is  least 
risk  of  injury  to  the  foliage.     The  insecticide  also  will  be 


WHEN  TO   SPRAY.  157 

more  effective  if  applied  soon  after  the  caterpillars  hatch. 
As  the  young  gypsy-moth  caterpillars  hatch  at  intervals 
from  the  latter  part  of  April  until  the  middle  of  June,  and 
as  the  leaves  are  constantly  growing  during  the  early  part 
of  the  season,  thereby  offering  daily  more  fresh  unpoisoned 
surface  upon  which  the  caterpillars  may  feed,  it  may  be  neces- 
sary to  spray  once  or  twice  more  in  May  or  June.  Spraying 
with  the  best  insecticides  known  (arsenate  of  lead  excepted) , 
if  done  late  in  the  season,  has  little  effect  on  the  gypsy-moth 
caterpillars  where  they  are  numerous,  as  they  will  strip  all 
foliage  from  the  trees  before  being  seriously  affected  by  the 
poison.  The  uselessness  of  such  spraying  is  shown  by  the 
illustrations  in  plates  IX.,  XI.  and  XVI.  The  caterpillars 
thus  destroyed  the  foliage  in  the  Swampscott  woods  early  in 
August,  after  the  trees  had  been  sprayed  twice  with  Paris 
green.* 

It  is  well  not  to  spray  fruit  trees  when  in  blossom.  If 
sprayed  at  all  at  that  time,  the  work  should  be  done  with  a 
nozzle  throwing  a  fine,  mist-like  spray.  A  coarser  spray  is 
likely  to  injure  the  blossoms,  as  well  as  to  wash  off  the 
pollen.  There  is  danger  also  of 'poisoning  bees.  Prof.  F. 
M.  Webster,  entomologist  of  the  Ohio  experiment  station, 
has  experimented  by  spraying  apple  trees  in  full  bloom  and 
giving  bees  access  under  natural  conditions  to  the  sprayed 
blossoms.  Many  of  the  bees  which  visited  the  trees  died 
suddenly,  as  well  as  the  young  larvae  of  a  brood  from 
uncapped  cells.  Arsenic  was  found  in  the  contents  of  the 
abdomen  as  well  as  on  the  external  parts.  The  bees  all  gave 
evidence  of  having  died  from  the  effects  of  arsenic  which 
could  only  have  been  introduced  from  without  the  hive.  If 
the  pollen  is  washed  off  tlie  blossoms  by  the  spraying  and 
the  bees  which  distribute  pollen  are  killed  by  the  poison,  the 
spraying  of  fruit  trees  when  in  blossom  will  affect  their 
fruitfulness. 

Spraying  should  not  be  done  during  showers  or  after 
showers  before  the  leaves  dry,  or  when  a  heavy  dew  is 
on  the  foliage.  When  spraying  is  done  during  showers, 

*  Many  of  the  failures  that  have  been  recorded  in  spraying  for  other  insects  may 
be  traced  to  the  fact  that  the  work  was  done  too  late,  and  not  until  after  the  injury 
was  so  serious  that  the  spraying  could  not  stop  it  in  time  to  save  the  foliage. 


158  THE   GYPSY  MOTH. 

much  of  the  poison  will  be  washed  off  or  gather  in  spots. 
If  the  trees  are  sprayed  in  dry  weather  or  at  a  time  in  the 
day  when  the  leaves  are  dry,  the  poison  adheres  to  the  leaves 
as  it  falls  and  is  thus  most  effective. 

How  to  Spray  for  the  Gypsy  Moth. 

In  many  cases  spraying  for  insect  pests  is  a  failure.  Where 
tender  plants  and  choice  fruit  trees  are  sprayed,  more  harm 
than  good  is  often  done.  This  is  not  to  be  attributed,  how- 
ever, to  the  method,  but  to  either  poor  machinery  or  to 
ignorance  or  carelessness  in  the  use  of  insecticides.  When 
spraying  is  thoroughly  and  carefully  done  according  to  the 
rules  given  by  the  best  authorities,  it  will  almost  always  give 
good  results  with  most  leaf-eating  insects.  Yet,  as  has  been 
shown,  the  most  careful  spraying  with  the  best  insecticides 
may  fail  to  check  the  gypsy  moth.  If  spraying  is  done 
when  the  caterpillars  are  young  and  feeding  mostly  on  the 
lower  surface  of  the  leaves,  it  will  be  most  effective.  Use 
not  less  than  fifteen  pounds  of  arsenate  of  lead  and  two 
quarts  of  glucose  to  one  hundred  and  fifty  gallons  of  water. 
Be  sure  that  the  acetate  of  lead  is  dissolved  in  water  (warm 
if  need  be)  before  it  enters  the  tank.  Stir  the  mixture  con- 
stantly and  spray  evenly  and  thoroughly  with  a  fine  spray. 
If  this  does  not  kill,  double  the  dose. 

Spray  fruit  trees  to  as  high  a  point  as  possible  from 
the  ground  by  the  use  of  a  long  pole  or  extension  with  any 
nozzle  which  will  throw  a  very  fine  spray,  spraying  always 
in  such  a  way  as  to  reach  the  under  side  of  the  leaves. 

On  tall  shade  or  forest  trees  spraying  may  be  best  accom- 
plished by  the  use  of  a  ladder.  A  nozzle  which  will  throw 
a  coarse  spray  to  a  distance,  like  the  Gem,  Lowell,  Nixon 
or  McGowen,  may  be  used.  Often  the  lower  limbs  may  be 
sprayed  from  the  ground  by  means  of  a  pole.  The  pole  can- 
not be  so  well  handled  in  the  tree,  and  the  workman  can 
spray  best  by  climbing  up  the  main  trunks  and  branches 
and  spraying  from  below  as  he  climbs.  If  the  spraying  is 
done  later  in  the  season,  particular  attention  must  be  paid 
to  the  ends  of  the  branches  and  to  the  tops  of  the  trees,  for 
many  of  the  larger  caterpillars  crawl  to  the  very  tips  of  the 
branches  and  to  the  tops  of  the  trees  to  feed. 


PLANTS  INJURED.  159 


Injury  to  Plants  caused  by  Spraying. 
The  strong  prejudice  against  the  use  of  Paris  green  for 
spraying  which  was  met  with  in  Medford  in  1891  was  partly 
caused  by  the  belief  that  both  trees  and  garden  plants  would 
be  injured  or  killed  thereby.  This  belief  was  shared  by  many 
people  and  was  largely  based  upon  the  results  of  the  work 
of  the  first  commission,  as  observed  in  1890.  Many  indi- 
viduals who  had  experimented  with  London  purple  and  Paris 
green  in  an  attempt  to  protect  their  trees  had  succeeded 
only  in  destroying  the  foliage.  It  is  true  that  the  foliage 
of  many  trees  was  injured  in  1890,  and  that  to  a  less  extent 
this  occurred  in  the  work  of  1891.  Yet  much  of  the  appar- 
ent injury  was  effected  by  other  causes  than  spraying.  In 
the  investigation  of  complaints  that  the  foliage  of  trees  had 
been  burned,  it  was  found  that  in  some  cases  the  injured 
trees  had  not  been  sprayed.  In  at  least  one  case  the  sup- 
posed burning  was  caused  by  the  eifect  of  a  late  frost.  A 
blight  upon  fruit  trees  early  in  the  season  closely  resembled, 
upon  superficial  examination,  the  appearance  produced  by 
arsenical  burning.  Later  in  the  season,  during  the  drier 
portion  of  the  summer,  many  leaves  on  trees,  which  had 
not  been  sprayed,  turned  yellow  and  fell,  presenting  much 
the  same  appearance  as  was  observed  on  forage  which  had 
been  burned  by  spraying.  Many  reports  were  received  that 
trees  had  been  killed  by  spraying,  but  in  most  of  these  cases 
it  was  not  clearly  proved  that  death  was  not  due  to  some 
other  cause.  Still  there  is  evidence  that  some  young  trees 
were  either  killed  by  spraying  or  were  so  weakened  by 
burning  or  defoliation  resulting  from  spraying  that  they 
succumbed  to  the  heat  of  the  summer.  Such  a  result  is  un- 
usual, however.  An  apple  tree  which  was  sprayed  in  1890 
with  the  contents  of  fifteen  tanks  of  the  Paris  green  mixture, 
each  tank  containing  a  pound  of  Paris  green,  was  not  per- 
manently injured.  It  is  said  that  many  young  and  tender 
plants  in  gardens  were  not  only  seriously  injured  but  actually 
killed  by  spraying ;  yet  where  this  happened  it  was  prob- 
ably due  to  some  ignorance  or  carelessness  in  the  use  of  the 
insecticide.  Some  species  of  trees  a-re  more  susceptible  than 
others  to  the  effects  of  the  poison.  The  foliage  of  plum 


160  THE   GYPSY  MOTH. 

trees  and  especially  that  of  peach  trees  is  often  destroyed 
by  an  application  which  will  not  injure  the  apple  or  many 
other  species.  There  appears  to  be  a  difference  among 
varieties  of  trees  of  the  same  species  in  their  susceptibility 
to  poison,  and  some  individuals  of  the  same  variety  seem 
more  susceptible  to  injury  than  others.  This  is  also  true 
of  shrubs  and  garden  plants. 

Causes  of  the  Burning  Effect. 

We  have  already  stated  that  the  burning  of  foliage  by 
arsenites  appears  to  be  caused  by  the  soluble  arsenic  in  the 
insecticide ;  yet  it  is  known  that  poisons  like  Paris  green, 
which  are  comparatively  insoluble  in  water,  will  burn  the 
foliage  under  natural  conditions  if  applied  in  great  strength. 
This  seems  to  indicate  that  the  arsenic  on  the  leaf  is  dis- 
solved more  or  less  by  dews  and  rains,  the  dehydrating 
effects  of  the  sun's  rays,  a  moist  atmosphere  or  the 
exhalations  from  the  leaf,  or  by  all  combined.  We  have 
noted  that  although  experiments  with  arsenites  performed 
in  a  dry  atmosphere  in  the  laboratory  produced  no  burn- 
ing effect,  the  same  strength  of  material  burned  badly  out 
of  doors.  Professor  Fernald's  experiments  in  the  insectary 
indicate  that  Paris  green  burns  more  in  warm  damp  weather 
than  in  cool  dry  weather.*  The  larger  the  amount  of 
arsenic  deposited  on  the  leaf  the  greater  will  be  the  amount 
eventually  dissolved,  and  the  greater  the  burning  effect.  If 
the  liquid  is  distributed  evenly  in  minute  drops  over  the  leaf, 
there  is  less  danger  of  burning  than  if  it  is  distributed  in 
large  drops,  or  if  the  tree  is  so  copiously  showered  as  to 
cause  the  arsenic  to  settle  and  accumulate  in  spots  upon  the 
leaf.  Wherever  such  accumulations  occur,  the  burning  is 
the  more  serious  and  the  injury  spreads  from  the  burned 
spots.  Therefore,  there  will  be  the  least  burning  from  a 
fine  spray,  lightly  and  evenly  distributed. 

How  to  prevent  Burning  the  Foliage. 

What  should  be  done  and  what  avoided  to  prevent  or  lessen 
the  burning  of  the  foliage  may  be  summarized  as  follows :  — 

*  Bulletin  No.  19,  Hatch  Experiment  Station,  page  118,  May,  1892. 


PREVENTION  OF  BURNING.  161 

1.  Avoid  the  use  of  London  purple. 

2.  If  Paris  green  is  used,  keep  the  spraying  liquid  con- 
stantly and  thoroughly  agitated. 

3.  Use  only  a  very  fine  spray  and  distribute  it  lightly. 
This  applies  especially  to  tender  plants  and  valuable  fruit 
trees  where  burning  may  mean  serious  loss. 

4.  Do  not  let  the  spraying  liquid  stand  in  the  tank  but 
use  it  as  soon  as  mixed. 

5.  Spray  early  in  the  season  when  the  injury  to  leaves 
will  be  least. 

6.  If  Paris  green  does  not  give  good  results,  use  arsenate 
of  lead,  which  will  not  burn  if  properly  mixed  and  applied. 

Reports  of  Injury  to  Man  and  Animals  by  Spraying. 
The  prejudice  against  spraying  in  Medford  and  other 
towns  was  intensified  by  the  belief  that  there  was  danger  of 
fatal  poisoning  to  man  and  animals.  When  the  spraying 
was  in  progress,  sensational  reports  were  circulated.  State- 
ments were  made  in  the  daily  press  that  a  man  had  died 
from  the  effects  of  chewing  leaves  taken  from  trees  sprayed 
in  Medford,  and  that  a  child  had  been  fatally  poisoned  by 
eating  bread  and  butter  on  which  some  of  the  spray  had 
fallen  from  the  trees.  On  this  at  least  one  newspaper  editor 
advised  his  readers  to  shoot  at  sight  the  workmen  employed 
in  spraying.  It  was  reported  that  there  was  great  danger 
from  eating  sprayed  fruit.  Several  quarts  of  cherries  which 
had  been  taken  from  sprayed  trees  and  preserved  in  jars  were 
analyzed,  and  no  trace  of  arsenic  was  found.  Yet  even  before 
they  were  analyzed,  it  was  reported  that  they  had  been  sent 
to  Amherst  and  that  arsenic  enough  had  been  found  on  them 
to  kill  a  dozen  people.  A  large  portion  of  the  cherries  on 
these  trees  were  stolen  by  boys  or  given  away,  yet  no  im- 
mediate mortality  occurred  among  the  juveniles  of  the  neigh- 
borhood. It  was  frequently  reported  that  people  had  been 
badly  poisoned  by  having  a  spray  thrown  in  their  faces.  It 
is  possible  that  this  statement  had  some  slight  foundation  in 
fact.  While  in  eating  fruit  there  is  little  danger  of  the  con- 
sumption of  sufficient  poison  to  have  any  appreciable  effect 
on  the  system,  there  is  a  certain  amount  of  danger  from  the 
absorption  or  inhalation  of  arsenic,  and  great  care  should 


162  THE   GYPSY  MOTH. 

be  always  exercised  in  its  use.  About  ten  per  cent,  of  the 
men  employed  in  spraying  suffered  more  or  less  from  arseni- 
cal poisoning.  Some  appeared  to  be  much  more  susceptible 
to  its  effects  than  others.  This  subject  is  more  fully  treated 
in  Appendix  F,  where  instances  of  the  ill  effects  produced  by 
the  careless  use  of  arsenic  are  given.  Numerous  sensational 
tales  were  promulgated  in  regard  to  the  effect  produced  on 
animals  by  eating  grass  or  foliage  poisoned  with  Paris  green. 
That  there  is  no  danger  of  serious  results  to  the  larger 
domestic  animals  from  ordinary  spraying  has  been  proved 
by  Prof.  A.  J.  Cook's  experiments.*  He  fed  to  his  horse 
and  to  sheep  grass  on  which  the  poison  had  been  allowed 
to  drop  copiously  from  sprayed  trees.  We  have  frequently 
fed  a  horse  in  the  same  way  without  any  apparent  harm  to 
the  animal.  A  Medford  milkman  was  accustomed  to  take 
as  a  gift  the  grass  which  people  feared  to  use,  it  having  been 
cut  on  lawns  where  the  trees  had  been  sprayed.  This  grass 
formed  the  principal  food  of  his  cows  during  the  summer  and 
they  showed  no  ill  effects.  At  one  farm  in  Somerville,  where 
the  trees  were  liberally  sprayed,  three  cows  suddenly  died. 
A  suit  was  threatened,  but  on  account  of  lack  of  evidence  it 
never  came  into  court,  f  Several  flocks  of  fowls  were  stricken 
with  sudden  mortality  immediately  after  the  trees  which  hung 
over  hen  yards  had  been  sprayed.  Fowls  show  a  great  sus- 
ceptibility to  arsenical  poisons.  It  is  a  question,  however, 
whether  the  fowls  were  killed  by  eating  poisoned  caterpillars 
or  grass  on  which  the  spraying  liquid  fell,  or  whether  they 
did  not  die  from  some  epidemic  disease.  The  matter  was 
not  fully  investigated,  One  instance  was  noted  where  a  hen 
died  just  as  the  workmen  walked  into  the  yard  to  begin 
spraying.  The  owner  was  immediately  notified  so  that  the 
impression  might  be  avoided  that  it  was  killed  by  Paris 
green.  J 


•  Bulletin  No.  63,  Agricultural  College  of  Michigan  Experiment  Station,  August, 
1889. 

t  Cows  have  fed  without  apparent  injury  on  grass  under  trees  which  have  been 
twice  sprayed  with  arsenate  of  lead  at  a  strength  of  fifteen  pounds  to  one  hundred 
and  fifty  gallons  of  water. 

J  If  wild  birds  are  likely  to  be  destroyed  by  eating  poisoned  vegetation  or  poisoned 
insects,  the  benefits  derived  from  spraying  must  be  largely  discounted,  as  birds  are 
most  useful  as  insect  destroyers. 


CONTACT  INSECTICIDES.  163 

Spraying  with  Contact  Insecticides. 

When  it  was  seen  that  spraying  the  foliage  with  Paris 
green  had  little  effect  on  the  larger  gypsy-moth  caterpillars, 
experiments  were  made  with  insecticides  which  were  intended 
to  kill  by  contact.  This  was  done  to  find  a  means  of  dispos- 
ing of  the  masses  of  caterpillars  which  did  not  seem  to  be 
much  affected  by  the  use  of  Paris  green  and  which  clustered 
on  many  trees  where  tire  could  not  be  used.  Contact  in- 
secticides, when  of  a  strength  sufficient  to  kill  the  gypsy- 
moth  caterpillars,  are  likely  to  cause  injury  when  used  on  the 
foliage.  Therefore  they  can  only  be  used  to  advantage  as  a 
last  resort  where  the  caterpillars  have  stripped  trees  or 
where  they  are  clustered  in  such  numbers  on  the  trunks 
as  to  make  it  less  expensive  to  spray  with  an  insecticide 
than  to  kill  them  by  hand. 

Kerosene  emulsion  was  first  tried.  A  strong  emulsion 
gave  fairly  good  results  but  its  preparation  in  the  field  was 
not  economical.  The  only  way  in  which  it  could  be  made  to 
give  satisfactory  results  was  to  mix  it  at  a  central  point  and 
distribute  it  to  the  different  towns.  When  it  was  made  in 
the  field  the  men  did  not  get  uniform  results. 

Fish  oil  and  whale  oil  soap  gave  better  satisfaction  when 
used  as  follows  :  — 

Take  one  pound  of  whale  oil  soap  and  slice  into  thin, 
small  pieces.  Place  the  pieces  of  soap  in  a  pail  and  add 
about  a  gallon  of  boiling  or  nearly  boiling  water ;  then  stir 
until  the  soap  is  dissolved ;  dilute  at  the  rate  of  one  pound 
of  soap  to  twenty  gallons  of  water.  This  formula  was  pre- 
pared by  Mr.  E.  P.  Felt. 

Solutions  made  from  soap  powders  also  proved  effective. 
The  following  formula  was  prepared  by  Supt.  F.  H.  Jones  :  — 

Place  one  pound  of  "Gold  Dust"  in  a  pail;  add  one 
gallon  of  lukewarm  (not  hot)  water ;  stir  briskly  until  the 
powder  is  dissolved ;  then  add  three  gallons  of  cold  water ; 
stir  well. 

Where  the  larvae  and  pupae  are  clustered  together  on  the 
trunks  of  trees  and  in  stone  walls  or  other  sheltered  places, 
they  should  be  well  drenched  with  the  solution.  The  hand 
tank  (Fig.  1,  page  120)  and  Gem  nozzle  were  found  useful 


164  THE   GYPSY  MOTH. 

in  spraying  with  contact  insecticides.  A  tree  in  Swamp- 
scott,  the  trunk  of  which  was  covered  with  caterpillars, 
was  sprayed,  killing  nearly  all  at  one  spraying.  Excellent 
results  were  obtained  wherever  the  liquid  was  carefully 
mixed  and  applied.  It  is  poor  economy,  however,  to  use 
contact  insecticides  except  where  the  larvae  are  very  numer- 
ous, for  elsewhere  they  may  be  more  rapidly  and  cheaply 
killed  by  hand,  either  by  burlapping  the  trees  or  by  other 
methods. 

While  the  use  of  soap  powders  upon  the  gypsy  moth  has 
some  advantages,  it  is  not  to  be  recommended  except  in  the 
most  extreme  cases  and  with  the  exercise  of  great  care  and 
judgment. 

MEASURES  FOR  DESTROYING  ALL  FORMS  or  THE  MOTH. 
The  methods  thus  far  described  have  each  been  intended 
for  the  destruction  of  a  particular  form  of  the  moth.  The 
methods  hereinafter  described  are  intended  to  facilitate  or 
secure  the  destruction  of  all  forms  of  the  moth,  and  have 
been  used  with  a  view  to  preventing  the  creature's  spread 
and  securing  its  extermination.  It  has  sometimes  become 
necessary  to  destroy  all  vegetation  in  an  infested  spot  in 
order  to  prevent  the  moth's  rapid  spread  and  wide  dissemina- 
tion. For  this  purpose  fire  and  the  axe  have  been  resorted  to. 

Gutting  and  Burning. 

As  an  exterminative  method  for  use  in  wooded  tracts,  the 
felling  of  trees  and  their  destruction,  together  with  that  of 
all  other  vegetation,  by  means  of  fire  has  no  equal  in  point 
of  expedition  and  economy.  This  can  only  be  done  advan- 
tageously, however,  on  lands  where  the  timber  is  of  little 
value,  as  the  damage  caused  and  expense  incurred  by  treating 
valuable  woodland  in  this  way  would  be  great.  This  method 
is  expedient  only  where  a  badly  infested  spot  is  found  in 
woods  not  otherwise  infested  and  where  by  vigorous  and 
immediate  exterminative  methods  the  pest  may  be  stamped 
out.  When  a  colony  of  this  kind  is  discovered,  the  trees  may 
be  felled  to  best  advantage  in  the  fall  or  early  winter.  At  the 
same  time  the  undergrowth  can  be  cut  close  to  the  ground  and 
burned  together  with  the  tree-brush,  or  it  may  be  left  to  dry 


SPRAYING  APPARATUS.  149 

a  rotary  motion  on  the  screw  bearing  of  the  inner  tube,  and 
the  spraying  solution  is  forced  out  through  the  circular  space 
thus  opened  between  the  point  of  the  inner  tube  and  the 
inner  surface  of  the  outer  tube,  which  surround  it.  By 
turning  the  outer  tube  the  density  of  the  spray  and  the  dis- 
tance to  which  it  can  be  thrown  are  regulated. 

The  Gem  nozzle  (Plate  XXIV.,  Fig.  4)  is  made  on  the 
same  principle  as  the  Lowell.  In  using  these  nozzles  a  strong 
pressure  is  required  to  insure  a  fine  spray. 

For  spraying  orchard  trees  and  shade  trees  of  ordinary 
size,  light  hand  ladders  were  found  to  be  very  serviceable. 
But  when  the  tops  of  tall  street  elms  were  sprayed,  extension 
ladders,  thirty,  forty  or  even  sixty  feet  in  length,  were  nec- 
essary. A  heavy  extension  ladder  sixty-five  feet  in  length, 
such  as  is  used  by  firemen,  was  purchased  for  the  latter 
purpose.  This  ladder  could  be  readily  and  skilfully  handled 
by  six  men  with  the  aid  of  blocks  and  tackle.  The  small 
hand  ladders  were  carried  on  the  spraying  wagons  and  the 
larger  ones  by  hand  or  upon  wagons,  hand-carts  or  wheels, 
as  was  most  convenient.  Ladders  mounted  permanently 
upon  wheels  could  not  be  used  to  advantage  on  account  of 
the  uneven  nature  of  the  ground  where  much  of  the  spraying' 
was  done.  Ladders  twenty  to  twenty-five  feet  in  height  with 
braces  so  made  that  they  could  be  set  up  like  step-ladders 
were  used  at  first,  but  they  were  unwieldy  and  it  was  soon 
seen  that  more  effective  work  could  be  done  by  using  light 
ladders  and  climbing  into  the  trees  themselves.  In  climbing 
fruit  and  shade  trees  care  must  be  taken  not  to  injure  the 
branches. 

Machinery  for  Spraying  Orchard  Trees  and  Garden  Plants. 

Although  in  spraying  small  gardens  and  orchards  any  good 
tank  or  pump  may  be  used,  the  heavy  and  more  cumber- 
some outfits  are  not  necessary.  A  small  portable  tank  and 
pump  which  can  be  taken  about  by  the  operator,  either 
attached  to  his  person  or  upon  a  wheelbarrow,  will  suffice 
for  all  the  spraying  required  in  small  estates. 

For  spraying  garden  plants  and  small  fruit  trees  the 
"  knapsack  pump,"  which  is  fastened  on  the  shoulders, 
has  been  orten  recommended  for  use  in  small  gardens  and 


CUTTING  AND  BURNING.  165 

where  it  falls  and  burned  later  with  the  wood  by  means  of  a 
running  fire.  Fire  will  dispose  of  the  eggs  upon  the  trees  and 
undergrowth,  yet  many  will  remain  among  the  dried  leaves 
on  "the  ground.  In  order  to  secure  the  destruction  of  the 
caterpillars  which  hatch  from  these,  the  territory  cleared 
should  be  thoroughly  burned  over  in  the  spring  with  the 
cyclone  burner.  This  should  be  done  shortly  after  the  young 
caterpillars  hatch.  The  cutting  and  burning  should  extend 
for  several  hundred  feet  beyond  the  utmost  confines  of  the 
infested  spot.  The  immediate  effect  of  this  treatment  will 
be  to  destroy  all  vegetation  above  ground,  and  as  a  conse- 
quence any  young  caterpillars  not  reached  by  the  flames  will 
starve.  From  the  stumps  of  deciduous  trees  cut  down, 
sprouts  will  in  time  spring  up.  The  burning  will  not  kill 
the  roots  and  a  new  growth  of  trees  will  finally  develop. 
There  will  be  no  sprouts  from  the  older  coniferous  trees, 
as  they  do  not  renew  their  growth  in  this  way,  but  are 
replaced  by  deciduous  trees.  The  burning  is  not  entirely 
without  beneficial  effect  on  the  land.  The  ashes  resulting 
from  the  combustion  of  wood  and  dry  leaves  stimulate  the 
growth  of  such  roots  as  are  buried  in  the  ground  or  beneath 
the  leaves  and  which  send  forth  shoots  under  the  influence 
of  sun  and  rain.  Within  a  few  months  the  entire  burned 
area  will  be  covered  with  a  growth  of  young  plants  and  trees. 

A  locality  in  Woburn  where  timber  land  is  being  cleared 
in  this  way  is  shown  in  our  illustration  (Plate  XXIX.). 
The  appearance  of  this  woodland  when  attacked  by  the 
gypsy  moth  may  be  seen  by  referring  to  Plate  XVII.  The 
owner  was  willing  that  the  ground  should  be  cleared  in 
order  to  secure  relief  from  the  pest.  The  trees  were  first 
cut  down  and  the  wood  cut  in  eight-foot  lengths  and  the 
brush  piled  and  burned,  leaving  the  land  ready  for  the  final 
burning  with  the  cyclone  burner  in  the  spring. 

Valuable  woodlands  generally  infested  have  been  treated 
by  clearing  away  the  undergrowth  so  as  to  leave  nothing  on 
the  ground  for  the  insects  to  feed  upon.  In  this  work  great 
care  must  be  taken  to  avoid  injuring  the  trees  by  making  too 
hot  a  fire  about  their  trunks.  It  is  better  to  rake  away  the 
dead  leaves  and  undergrowth  from  the  bases  of  the  trees  and 
burn  them  than  to  risk  girdling  the  trees  by  running  a  hot 


166  THE   GYPSY  MOTH. 

fire  close  to  their  trunks.  They  may  then  be  banded  with 
insect  lime  so  that  the  caterpillars  may  find  nothing  on  which 
to  feed,  or  they  may  be  burlapped  and  the  caterpillars  caught 
under  the  burlaps.  This  method  will  not  injure  the  growing 
timber,  and  if  a  cleared  grove  is  desired  the  timber  may  be 
thinned  by  cutting  away  the  least  valuable  trees.  This  will 
render  the  later  treatment  less  expensive. 

In  1891  nearly  all  the  trees  were  felled  on  a  tract  of  more 
than  one  hundred  acres  near  Myrtle  Street,  Medford,  where 
the  moths  were  first  introduced.  (See  Plate  XXX.)  The 
undergrowth  was  then  burned  by  a  running  fire.  The  ex- 
termination of  the  moths  at  that  place  was  not  then  attempted, 
but  the  work  was  done  as  an  experiment  in  preventing  their 
increase  and  spread  from  a  badly  infested  locality.  As  such 
it  was  a  success.  A  fire  run  through  dry  leaves  and  under- 
growth before  the  middle  of  May  will  destroy  the  greater 
portion  of  the  young  larvse  if  done  when  they  are  small,  and 
when  the  dry  vegetation  burns  with  a  quick  heat. 

When  worthless  and  badly  infested  trees  are  found  in 
orchards  or  elsewhere,  the  most  effectual  and  economical 
method  is  to  cut  and  burn  them.  Such  trees  are  usually 
full*  of  holes,  cracks  and  cavities,  and  in  such  hiding  places 
all  forms  of  the  moth  are  found  in  numbers.  The}'  can  be 
immediately  disposed  of  by  burning  the  trees,  thereby  obvi- 
ating the  necessity  of  further  search  and  treatment. 

There  is  much  waste  land  covered  with  undergrowth  and 
scrubby  trees  in  the  infested  region.  It  receives  no  care 
from  its  owners,  being  held,  not  for  its  productive  value,  but 
for  speculative  purposes.  Fire  often  runs  over  such  land, 
killing  the  bushes  and  young  pines  and  injuring  the  larger 
growth  so  that  it  is  comparatively  worthless.  Such  land 
can  be  cut  over  with  little  or  no  loss  to  the  owner ;  indeed, 
clearing  may  often  enhance  its  value.  It  is  not  well  to  cut 
the  growth  during  the  spring  months,  when  the  caterpillars 
are  upon  it,  as  they  will  be  disturbed  by  such  work  and 
scattered  in  all  directions.  It  is  much  better  to  cut  over 
such  land  in  the  fall,  and  burn  the  brush  as  it  is  cut  or  let 
it  lie  on  the  ground  until  it  is  well  dried  and  then  run  fire 
through  it,  destroying  as  many  of  the  eggs  of  the  gypsy 
moth  as  possible.  Then  when  the  larvae  hatch  in  the  spring, 


i! 


9& 
SI 


SI 

ii 


BURLAPPING.  167 

there  will  be  nothing  for  them  to  climb  upon,  and  they  may 
be  all  destroyed  by  burning  the  ground  over  with  a  cyclone 
burner.  (See  Plate  XX.)  If  it  is  desired  to  prevent  a  new 
growth  of  brush,  the  ground  should  be  burned  over  in  August 
while  the  sap  is  in  the  plants,  and  again  in  the  following 
spring.  After  such  treatment  the  plants  will  not  so  readily 
sprout  and  a  frequent  repetition  of  the  burning  will  result 
in  killing  their  roots. 

Burlapping. 

Early  in  the  summer  of  1891  burlap  or  bagging  was  first 
used  by  the  employees  of  the  State  Board  of  Agriculture  as 
a  means  of  assembling  the  gypsy-moth  caterpillars  so  that 
they  might  be  readily  found  and  destroyed.  It  was  noticed 
that  before  the  caterpillars  had  attained  half  their  growth, 
they  daily  left  the  leaves  on  which  they  had  fed  during  the 
night  and  clustered  in  sheltered  places,  such  as  cavities  in 
the  trunks  of  trees  or  the  under  sides  of  branches  or  other 
natural  objects.  They  began  thus  swarming  in  the  second 
week  in  June.  As  they  grew  larger  the  tendency  to  seek 
shelter  during  the  day  became  more  and  more  noticeable. 
They  often  wandered  in  search  of  shelter,  leaving  trees 
which  did  not  offer  secure  hiding-places  and  retiring  to 
rubbish  heaps,  stone  walls  and  other  places  of  refuge  to 
pass  the  day.  It  was  seen  that  whenever  old  garments, 
cloth  or  paper  were  thrown  in  the  forks  or  wound  around 
the  trunks  or  branches  of  infested  trees,  the  shelter  of  such 
materials  was  sought  by  the  larvae  during  the  heat  of  the 
day.  The  bulky  nests  of  the  English  sparrow  also  served 
them  as  hiding-places. 

The  conclusion  having  been  reached  at  this  time  that 
spraying  with  Paris  green  was  only  partially  successful  in 
destroying  the  caterpillars,  other  means  of  destruction  were 
sought.  Experiments  were  made  to  find  an  inexpensive  yet 
durable  shelter  which  would  prove  attractive  to  the  cater- 
pillars, and  which  could  be  readily  examined  by  the  men, 
thus  serving  in  a  measure  the  purpose  of  a  trap.  A  cheap 
eight-ounce  burlap  was  found  to  be  the  best  material  for 
this  purpose.  A  large  quantity  of  baled  burlap  was  pur- 
chased and  cut  into  strips  about  twelve  inches  wide.  These 


168 


THE   GYPSY  MOTH. 


strips  were  made  into  rolls  which  the  workmen  carried  sus- 
pended from  the  shoulder.  Each  man  was  provided  with 
a  sheath  knife.  When  a  tree  was  to  be  "  burlapped,"  the 
end  of  a  roll  was  passed  around  the  trunk  at  a  height  of 
four  or  five  feet  from  the  ground,  and  enough  cut  off  to 
encircle  the  tree  and  lap  sufficiently  at  the  ends  to  allow 
for  shrinkage.  (See  Plate  XXXI.)  The  burlap  was  held 
in  place  by  twine  tied  around  both  tree  and  cloth.  (See 
Fig.  12,  a.)  The  upper  half  of  the  burlap  was  turned  down 
over  the  twine,  so  that  it  hung  like  a  tablecloth  suspended 
from  a  clothes  line,  and  made  a  band  of  double  thickness 
around  the  tree.  (See  Fig.  12,  b.)  Although  the  edges 
hung  loosely,  the  centre  was  bound  quite  securely  to  the 

trunk  of  the  tree.  If  the 
trunk  and  branches  offered 
no  better  hiding-places  to 
the  caterpillars,  most  of  those 
on  a  tree  would  crawl  down, 
morning  after  morning,  and 
seek  the  shelter  of  the  bur- 
lap, remaining  there  during 
the  greater  part  of  the  day. 
When  thus  assembled,  they 
were  killed  by  the  employees 
of  the  Board,  who  daily  went 
their  rounds  from  tree  to  tree,  raising  each  half  of  the  bur- 
lap separately  and  cutting  or  crushing  the  caterpillars  be- 
neath. Most  of  the  larvae  are  found  on  the  bark  behind 
the  burlap,  but  some  are  taken  between  the  folds.  When, 
in  the  search  for  larvae,  the  burlap  is  examined  for  the  first 
time,  it  is  left  turned  up  against  the  tree.  At  the  second 
examination  it  is  turned  down.  It  is  turned  up  at  the  next 
visit,  down  at  the  next  and  so  on.  By  following  this  plan 
any  band  that  has  been  missed  will  attract  attention.  Ex- 
perience indicates  that  the  number  of  caterpillars  taken  is 
not  materially  affected,  whether  the  band  is  left  up  or  down  ; 
yet  for  general  use  it  should  be  turned  down,  as  it  sheds  rain 
better  and  presents  a  neater  appearance. 

Where  the  caterpillars  are  massed,  they  may  be  quickly 
crushed  by  a  wisp  of  straw  or  a  wad  of  old  cloth.     Where 


a.  b. 

FIG.  12.    Manner  of  applying  the  burlap. 


PLATE  XXXI.      Putting  on  the  burlap. 


BURLAPPING.  169 

few  are  found,  they  may  be  cut  in  two  by  the  knife  and 
brushed  off  the  tree.  Care  must  be  taken  not  to  crush  them 
with  the  bare  hand,  as  their  hairs  when  brought  forcibly  in 
contact  with  the  skin  sometimes  cause  an  irritation  much 
like  that  produced  by  nettles. 

The  burlap  band  in  no  way  prevents  the  caterpillars  from 
ascending  or  descending  the  tree,  neither  does  it  entrap  those 
which  it  shelters.  But  it  was  soon  seen  that  most  of  the 
caterpillars  which  descended  the  tree  remained  under  the 
burlap  during  the  day,  and  that  others  which  were  restlessly 
roaming  about  on  the  ground  often  ascended  the  tree  to  the 
same  shelter.  Still  others,  fulJy  grown  and  ready  to  pupate, 
retired  to  the  cover  of  the  burlap  to  undergo  their  last  trans- 
formations, and  the  female  moths  emerging  would  often 
deposit  their  eggs  upon  or  beneath  it. 

The  larvae  seek  the  burlap  in  greatest  numbers  during  very 
hot  weather,  when  they  usually  come  down  the  trees  in  the 
early  morning  hours,  go  under  the  burlap  and  remain  there 
during  the  heat  of  the  day.  The  greater  number  keep  on 
the  shady  side  of  the  tree,  moving  with  the  sun  so  as  to 
avoid  its  direct  rays.  A  few  leave  the  burlap  during  the  day, 
but  most  of  them  remain  until  evening.  Observations  made 
on  a  small  apple  tree  showed  that  an  average  of  sixty-six 
per  cent,  of  the  larvae  on  the  tree  gathered  daily  under  the 
burlap.  This  habit  is  illustrated  by  Plate  XXXII. 

The  following  quotation  from  the  notes  of  Mr.  W.  L. 
Tower,  one  of  the  inspectors  engaged  in  the  gypsy-moth 
work,  indicates  that  the  antipathy  the  larger  larvae  have  for 
sunlight  is  not  uniformly  shared  by  the  younger  or  smaller 
individuals :  — 

The  small  larvae  on  the  tree  were  less  restless  and  were  disposed 
to  remain  longer  in  the  sun  than  were  the  older  ones.  Some  of 
the  smaller  ones  would  remain  all  day  in  the  sun  on  the  upper  side 
of  a  branch,  and  in  one  or  two  cases  when  placed  in  a  shady  place 
on  the  tree  returned  to  their  first  position  in  the  sunshine. 

The  burlap  band  to  be  effective  must  entirely  encircle 
the  trunk,  and  its  edges  must  hang  loosely.  If  under  the 
influence  of  sun  and  rain  it  shrinks  too  closely  to  the  tree, 
the  larvae  may  not  be  able  to  crawl  beneath  it.  This  may  be 


170  THE   GYPSY  MOTH. 

obviated  by  cutting  the  burlap  once  or  twice  from  its  edges 
nearly  to  the  twine  on  the  side  of  the  tree  opposite  the  lapped 
ends.  This  will  facilitate  the  entrance  of  the  larvse,  as  they 
can  easily  push  their  way  under  the  loose  corners.  If  a 
large  cord  is  used  to  bind  the  burlap  to  the  tree,  there  will 
be  more  room  left  under  the  upper  half  of  the  burlap  when 
it  is  turned  down.  When  the  larvae  are  very  numerous,  the 
burlap  may  be  tacked  on  and  pleats  taken  in  it,  to  afford 
more  room  for  the  larvse  to  pass  beneath.  On  large  trees, 
where  the  trunk  is  of  irregular  conformation,  tacks  will 
be  sometimes  required  to  hold  the  burlap  to  the  tree. 

To  those  familiar  with  the  habits  of  the  moth,  other  devices 
which  might  serve  a  similar  purpose  will  occur.  Old  tin 
cans  or  wisps  of  hay  or  straw  may  be  placed  in  the  forks  of 
branches  or  near  the  roots  of  trees  or  beneath  hedges  to 
attract  the  caterpillars,  which  may  be  then  disposed  of  by 
fire.  Old  blankets  hung  on  fences  or  walls  near  infested 
trees  will  collect  great  numbers  of  caterpillars. 

When  caterpillars  were  found  to  be  plentiful  in  shrub- 
bery, stakes  with  pieces  of  burlap  attached  were  frequently 
driven  into  the  ground  in  the  midst  of  the  bushes.  This 
made  an  attractive  shelter  for  the  caterpillars,  and  many  were 
assembled  and  destroyed.  Burlap  was  often  left  in  the  forks 
of  branches  or  thrown  over  rubbish  or  stone  heaps  in  badly 
infested  localities.  If  it  was  repeatedly  examined,  many 
caterpillars  were  found  and  destroyed.  It  was  early  noted 
that  not  all  the  caterpillars  would  come  down  from  the  larger 
trees,  such  as  street  elms,  but  that  some  of  them  would 
remain  in  the  upper  part  of  the  tree.  In  such  cases  bur- 
laps were  banded  about  the  trunk  or  branches  at  a  height  of 
twenty  or  twenty-five  feet  from  the  ground.  An  examina- 
tion of  these  burlaps  necessitated  the  use  of  a  ladder,  but 
the  results  often  justified  the  time  and  labor  expended. 

The  only  considerable  expense  required  by  the  burlapping 
method  is  that  of  labor.  To  secure  the  best  results  the 
bands  must  be  examined  each  day  so  long  as  any  form  of  the 
moth  can  be  found  beneath  them.  Old  cloth  will  answer 
the  purpose  equally  as  well  as  burlap. 

There  are  no  valid  objections  which  can  be  urged  to  the 
use  of  burlap.  There  seems  to  be  no  injury  to  the  tree 


PLATE   XXXII.      Section   of   burlap  band  raised,    showing   gypsy   moth. 

caterpillars  that  had  gathered  beneath  it  on  the 

trunk  of  an  eim  tree. 


BURLAPPING.  171 

from  its  use,  although  if  it  is  not  visited  often  and  watched 
carefully,  other  insects  injurious  to  trees  will  use  it  as  a 
hiding-place.  In  the  fall  the  larvae  of  the  codling  moth 
(Carpocapsa  pomonella.  Linn.)  will  crawl  under  the  burlap 
and  gnaw  away  the  bark  while  preparing  a  place  to  pupate  ; 
but  if  the  burlap  is  watched  and  all  injurious  insects  found 
beneath  it  destroyed,  its  use  will  prove  of  great  benefit  to 
i  the  tree.  Should  it  be  applied  to  very  young  fruit  trees 
(which  is  seldom  necessary,  as  a  cloth  thrown  in  a  fork 
of  the  tree  may  be  used  in  such  cases),  there  may  be  some 
little  danger  that  the  cord,  if  large,  will  shrink  too  tightly 
and  crease  the  bark  of  the  growing  tree. 

Though  the  use  of  the  burlap  for  the  destruction  of  the 
gypsy  moth  grew  out  of  observation  and  experiment  by  the 
employees  of  the  State  Board  of  Agriculture,  later  research 
in  the  literature  of  economic  entomology  showed  that  similar 
devices  had  been  used  in  the  past  for  other  insects. 

Dr.  Harris,  in  his  report  on  the  injurious  insects  of  Massa- 
chusetts (first  published  in  1841),  writes  as  follows  of  the 
use  of  bands  for  attracting  the  larvae  of  the  codling  moth :  — 

Mr.  Buirelle  says  that  if  any  old  cloth  is  wound  around  or  hung 
in  the  crotches  of  the  trees  the  apple  worms  will  conceal  themselves 
therein ;  and  by  these  means  thousands  of  them  may  be  obtained 
and  destroyed.* 

Kollar  wrote  of  the  use  of  the  same  method  in  Europe  :  — 

The  following  mode  of  destroying  the  insects  injurious  to  fruit 
trees,  communicated  to  me  by  M.  Scheffer  of  Modling,  is  so  simple 
and  yet  so  efficacious  that  I  cannot  do  better  than  to  lay  it  before 
my  readers.  M.  Scheffer  lays  loosely  rolled-up  pieces  of  old  cloth 
or  blotting-paper  in  the  forks  of  his  trees.  The  caterpillars  eat 
during  the  night  and  while  the  dew  is  on  the  leaves  in  the  morn- 
ing ;  but  they  seek  protection  from  the  heat  of  the  day,  and  creep 
into  these  rolls  for  that  purpose.  Thus  it  is  only  in  the  middle  of 
the  day  that  these  rolls  should  be  examined,  and  the  caterpillars 
concealed  in  them  destroy  ed.f 


*  "A  treatise  on  some  of  the  insects  injurious  to  vegetation,"  by  T.  W.  Harris, 
M.D.,  page  487.    See  also  "  New  England  Farmer,"  first  series,  Vol.  18,  page  398. 
t  "  Practical  Entomologist,"  Vol.  1,  page  83. 


172  THE  GYPSY  MOTH. 

As  Kollar  resided  in  Austria,  where  the  gypsy  moth  was 
sometimes  injuriously  abundant,  it  is  probable  that  this  crude 
means  of  assembling  the  caterpillars  was  used  in  destroying 
this  species  with  others. 

A  few  people  in  Medford  who  had  observed  the  habits  of 
the  gypsy  moth  had  also  used  similar  bandages  with  good 
effect  prior  to  1891.  (See  statements  of  James  Bean,  page 
29,  and  S.  F.  Weston,  page  30,  of  this  report.) 

The  burlap  bands  are  used  most  successfully  on  trees  that 
are  well  kept  and  in  good  condition,  with  sound  and  smooth 
trunks  and  branches.  If  the  trees  were  originally  in  such 
condition  or  were  first  properly  prepared  for  the  work,  the 
moths  were  eradicated  from  many  localities  by  the  burlap- 
ping  method  alone.  When  trees  with  decaying  branches, 
hollow  trunks  and  rough  or  loose  bark  became  infested,  the 
caterpillars  often  preferred  the  shelter  offered  by  such  cavities 
and  inequalities  to  that  provided  by  the  burlap.  Many  of 
them  would  not  come  down  the  tree  to  the  burlap  until  the 
cavities  were  filled  or  covered,  the  dead  branches  cut  away 
and  the  loose  outer  bark  removed  by  scraping.  It  was 
necessary  also  to  remove  rubbish,  weeds  and  brush  from  the 
ground  about  the  trees. 

There  are,  therefore,  four  auxiliary  processes  (all  beneficial 
to  trees  or  grounds)  which  must  be  resorted  to  to  ensure 
the  greatest  measure  of  success  in  the  use  of  burlap.  They 
are :  judicious  pruning  or  trimming  of  trees ;  treating  and 
filling  cavities ;  removing  loose  bark ;  removing  and  de- 
stroying rubbish,  undergrowth  and  weeds. 

Pruning  Infested  Trees. 

To  any  one  who  has  critically  examined  any  considerable 
number  of  orchard  or  wayside  trees  in  this  Commonwealth, 
the  insertion  here  of  an  exhaustive  treatise  on  the  pruning 
and  care  of  trees  would  seem  of  great  utility.  This,  how- 
ever, is  not  the  function  of  this  volume.  It  is  our  purpose 
to  consider  here  only:  (1)  the  proper  removal  of  dead,  de- 
caying or  broken  branches,  which,  if  allowed  to  remain,  offer 
hiding-places  for  the  gypsy  moth  and  other  injurious  insects  ; 
(2)  the  removal  of  clusters  of  small  shoots  or  suckers,  wrhich, 
growing  thickly  on  the  trunks  or  larger  branches,  offer  shel- 


PRUNING  INFESTED   TREES.  173 

ter  to  the  gypsy-moth  caterpillars,  which,  by  remaining  in 
such  hiding-places  instead  of  going  to  the  burlap,  may  escape 
destruction.  At  least  seventy-five  per  cent,  of  the  older 
orchards  in  the  region  infested  by  the  gypsy  moth  have  been 
either  ruined  or  greatly  injured  by  their  owners'  neglect  or 
improper  pruning  or  by  both.  Thousands  of  trees  have  been 
killed  by  having  large  limbs  chopped  or  sawn  off  or  other- 
wise mutilated  in  such  a  manner  that  the  exposed  and  unpro- 
tected stubs  have  died  and  communicated  decay  to  the  hearts 
of  the  trees.  This  condition  of  so  many  trees,  by  furnishing 
numberless  places  of  shelter  for  the  moth,  adds  greatly  to 
the  labor  of  extermination. 

Dangers  of  Bad  Pruning. — One  of  the  most  fruitful 
causes  of  hollows  in  trees  in  which  the  caterpillars  may  hide 
is  the  neglect  of  the  simplest  precautions  in  the  amputation 
of  large  limbs.  Wherever  we  go  in  the  country,  orchard 
trees  may  be  seen  with  trunks  disfigured  by  unsightly  protu- 
berances and  yawning  cavities.  Yet  projecting  dead  stumps 
such  as  have  assisted  in  bringing  the  trees  to  this  condition 
are  periodically  left  by  the  hand  of  the  bungling  pruner,  who 
will  continue  in  this  course  until  he  has  completed  the  ruin 
already  begun.  Such  trees  are  monuments  to  the  ignorance  or 
negligence  of  those  who  have  had  them  in  charge.  Intelligent, 
capable  men,  careful  of  their  other  material  interests,  continue 
year  after  year  to  "  butcher"  their  trees  in  this  outrageous 
manner,  as  their  fathers  did  before  them,  even  though  the 
results  of  such  work  are  constantly  before  their  eyes. 

The  growth  of  many  orchard  trees  has  been  badly  directed. 
They  have  been  pruned  "  up  into  the  air,"  so  that  their  long, 
tall,  slender  limbs  have  been  unable  to  withstand  the  fury 
of  the  gale  or  support  the  loads  of  ice  which  form  on  them 
during  winter  storms.  Weakened  as  such  trees  are  by  decay, 
the  action  of  the  wind  has  sent  their  greatest  branches  crash- 
ing down  in  ruin.  The  ice  storm  of  Nov.  5,  1894,  which 
visited  the  eastern  part  of  this  Commonwealth,  destroyed 
hundreds  of  apple  trees  by  breaking  down  most  of  their 
large  branches ;  yet  we  have  not  seen  a  sound,  vigorous, 
well-nourished  and  properly  pruned  tree  that  was  materially 
injured  by  that  storm.  Neither  was  it  always  the  older  trees 
which  succumbed,  for  some  of  the  oldest,  having  had  good 


174  THE   GYPSY   MOTH. 

care  and  therefore  not  being  weakened  by  the  almost  univer- 
sal decay,  upheld  their  loads,  survived  the  storm's  fury  and 
were  not  seriously  injured. 

It  is  far  better  never  to  prune  at  all  than  to  prune  in  an 
unscientific  manner.  Native  forest  and  fruit  trees  never 
pruned  by  the  hand  of  man  grow  to  maturity  in  better  con- 
dition than  those  in  many  orchards.  In  the  forest,  trees 
are  pruned  by  nature.  As  they  grow  upward,  the  dense 
shade  formed  by  their  tops  kills  the  lower  branches  by  de- 
priving them  of  the  sunlight.  These  branches  decaying  drop 
off  or  are  torn  away  by  the  wind.  Little  or  no  damage  to 
the  resinous  coniferous  trees  results  from  this  process.  As 
the  branches  usually  break  off  close  to  the  trunk,  and  the 
wood  is  so  filled  with  resin  as  to  exclude  water  and  parasitic 
fungi,  the  wounds  heal  readily  and  the  trunk  remains  per- 
fect. More  injury  is  likely  to  follow  to  deciduous  trees 
from  this  operation,  especially  when  the  branches  are  large, 
yet  wounds  caused  by  broken  branches  are  often  healed. 
The  breaking  is  most  likely  to  take  place  during  the  winter 
storms,  when  there  is  less  danger  of  injury  to  the  trunk  and 
bark.  Yet  serious  injury  is  often  done  and  the  weaker  trees 
are  frequently  killed  or  their  shape  is  ruined  by  this  process 
of  natural  pruning.  Such  pruning  as  is  required  for  the  pur- 
poses of  the  gypsy-moth  work  will  assist  in  forming  healthy 
growth  rather  than  retard  it. 

That  many  apple  trees  are  in  ruins  before  they  are  fifty 
years  old  is  almost  entirely  due  to  neglect  or  the  ruinous 
policy  pursued  in  their  handling.  Such  trees  well  cared 
for  might  continue  to  bear  fruitfully  for  a  century.*  A 
knowledge  of  vegetable  physiology  and  the  practical  applica- 
tion to  tree  culture  of  its  laws  is  greatly  needed  by  those 
who  have  the  care  of  trees.  A  knowledge  of  the  causes  of 
diseases  of  trees  and  the  means  of  their  prevention  is  also 
essential  to  the  farmer,  orchardist  and  forester. 

It  is  the  function  of  roots  to  fix  the  plant  in  the  soil  and  to 
absorb  from  it  water  and  the  soluble  organic  and  inorganic 
crude  material  which  is  needed  for  growth  and  development. 
It  is  now  believed  by  botanists  that  this  fluid,  which  we  will 

*  Apple  trees  in  an  orchard  planted  in  Medford  by  Gov.  John  Brooks  soon  after 
the  Revolutionary  War  have  borne  fruit  within  a  few  years. 


BAD  PRUNING.  175 

call  crude  sap,  charged  with  material  for  the  upbuilding  of 
the  tree,  is  absorbed  from  the  soil  by  the  roots  and  is  forced 
upward,  flowing  through  the  trunk  and  branches  to  the 
leaves,  where  it  is  elaborated  by  the  evaporation  of  water 
and  the  absorption  of  carbonic  acid  gas  from  the  air.  It 
then  finds  its  way  throughout  the  whole  tree,  even  to  the 
roots,  passing  through  the  soft  bast  cells  of  the  inner  bark 
just  outside  the  cambium  layer,  forming,  as  it  goes,  the  new 
wood  and  bark. 

It  may  be  stated  as  a  general  rule  that  there  can  be  no 
perfect  circulation  of  the  sap  and  no  long-continued  growth 
of  new  wood  or  bark  on  any  branch  or  stump  which  supports 
no  leaves.  It  would  appear,  then,  that  roots,  trunk  and 
branches  have  no  inherent  power  of  themselves  to  continue 
growth  and  extension,  but  must  depend  upon  the  action 
of  the  leaves  to  furnish  that  elaborated  nutriment  without 
which  their  continued  growth  and  development  is  impossible.* 
If  the  new  wood  is  formed  by  the  sap  in  its  descent  from  the 
leaves,  it  evidently  follows  that  if  the  projecting  stump  of 
an  amputated  branch  is  left  without  leaves  so 
placed  as  to  draw  the  sap  to  its  farthest  ex- 
tremity, there  to  be  elaborated  and  returned, 
it  must  die.f 

Effect  of  Bad  Pruning.— The  cut,  Fig. 
13,  represents  a  stump  left  on  a  street  tree 
by  the  workmen  employed  in  pruning  trees 
under  the  direction  of  the  city  forester  of 
one  of  our  Massachusetts  cities.  Around 

.     ,  .,  ,   FIG.  13.     Stump  of   a 

such   an   unprotected   stump   the   rain   and      branch  left  by  bad 
other  atmospheric  influences  soon  begin  the      pruc 
work  of  decay  between  the  bark  and  the  wood.     The  cam- 
bium layer,   lacking  circulation,  dries  up ;    insects   enter ; 

*  It  is  well  known  that  the  roots  will  for  a  time  perform  their  functions  without 
the  assistance  of  the  leaves,  and  that  growth  of  different  parts  of  the  tree  occurs  at  a 
time  when  there  are  no  leaves  upon  it.  But  this  growth  is  made  by  the  absorption 
of  water  by  the  roots  and  by  the  use  of  reserve  material.  If  a  tree  is  continually 
deprived  of  its  leaves  until  its  reserve  material  is  exhausted,  it  will  die. 

t  It  is  well  known  that  there  are  some  exceptions  to  this  rule.  Certain  vigorous 
trees  will  push  out  shoots  from  latent  buds  near  the  end  of  the  amputated  branch, 
and  leaves  are  formed,  which  by  their  functions  enable  the  tree  to  cover  the  wound. 
Willow  trunks  and  branches  deprived  of  their  leaves  and  left  upon  the  ground  have 
thrown  out  foliage  and  roots  and  grown  into  vigorous  trees. 


176 


THE   GYPSY  MOTH. 


the  bark  becomes  loosened,  warping  away  from  the  wood 
and  finally  falling  off.  This  condition,  so  familiar  to  ol>- 
serving  people,  may  be  seen  by  reference  to  Fig.  14,  which 
represents  an  extreme  case.  Nevertheless,  in  pruning, 
such  stumps  are  commonly  (we  might  say  usually)  left, 
not  only  by  farmers  and  orchardists,  but  also  by  the  em- 
ployees of  city  street  departments  and  park  commissions 
and  even  by  the  workmen  employed  in 
public  forest  reservations.  The  stump 
left  exposed  to  sun,  rain  and  the  action 
of  the  frost  cracks.  Water  enters  and 
decay  sets  in  which  gradually  extends 
through  the  wood  cells  down  into  the 
trunk.  Therefore  each  stump  left  pro- 
jecting eventually  produces  decay  in  that 
part  of  the  tree  with  which  it  connects. 
FIG.  14.  The  stump  dies  Fig.  15  shows  a  short  section  of  the  trunk 

back,  injuring  the  trunk.         ,,  ,  .   ,  ,  ,          . 

of  a  tree  on  which  such  a  stump  has  been 
left.  The  stump  shown  at  the  right  indicates  the  remark- 
able effort  made  on  the  part  of  the  tree  to  cover  the  wound ; 
yet  in  the  course  of  years  the  wood  has 
been  eaten  away  by  rot  and  the  wound 
has  never  healed.  Decay  has  entered 
the  heart  of  the  tree  and  is  fast  de- 
stroying it.  Had  the  branch  been  cut 
even  with  the  surface  of  the  trunk  and 
the  wound  properly  treated,  it  might 
have  been  covered  with  new  growth  of 
wood,  and  decay  might  have  been  pre- 
vented. 

Wounds  on  vigorous  trees  caused  by 
FIG",  is.  Atrunk'ri'inedby  tne    removal  of    small  branches  in  this 
bad  pruning.  manner  sometimes  heal  over  because  of 

the  small  size  of  the  branches  and  the  comparative  short- 
ness of  the  stumps.  But  as  the  stump  often  decays  be- 
fore the  wound  heals,  injury  to  the  tree  results,  and  in 
any  case  an  awkward  protuberance  is  formed  on  the 
trunk.  From  such  misshapen  parts  shoots  or  suckers  usu- 
ally spring.  Another  section  of  a  trunk  is  here  shown. 


METHOD  OF  PRUNING. 


177 


FIG.  16.    Excrescence 
caused  by  bad  pruning. 


(Fig.  16.)     The  wound  has  nearly  healed,  yet  decay  has  set 

in  and  an  unsightly  excrescence  has  been   formed   on   the 

trunk  of  the  tree  in  the  effort  of  healing.     If  the  wound  is 

well  covered  by  the  new  growth  of  wood 

before  injury  has  been  done  by  the  rot, 

the   progress   of  decay  is   stopped.     In 

order  to  heal  readily,  a  wound  caused 

by  the  removal  of  a  branch  should  be  so 

made  that  the  sap  on  its  way  to  the  roots 

may  come  in  contact  with  the  entire  edge 

of  the  wound  without   deviating  from  a 

direct  course. 

The  Proper  Method. — Evidently,  then, 
no  portion  of  the  amputated  branch  should 
be  left,  but  the  cut  should  be  made  close  to 
and  perfectly  even  with  the  outline  of  the 
trunk  or  limb  from  which  the  branch  is  removed ,  without  regard 
to  the  size  of  the  wound  thus  made.  When  this  is  done, 
the  elaborated  sap  flows  over  the  wound  from  the  edges, 
forming  callus  first  at  the  top  and  sides,  and  gradually 
covers  it  with  healthy,  straight-grained  wood.  The  wound 
is  thus  healed  over  and  the  decay  of  the  trunk  is  pre- 
vented. This  healing  is  gradual  and  may  require  years 
for  accomplishment,  especially  if  the  limb  removed  is  large 
and  the  tree  old  and  not  vigorous.  The  annual  wood-ring 
being  thickest  on  a  young  tree,  wounds  made  on  such  a  tree 
will  heal  more  quickly  than  on  an  old  tree.  Wounds  made 
near  the  top  of  a  growing  tree  heal  more  readily  than  those 
near  the  base,  for  the  reason  that  the  annual  wood-ring  is 
thickest  at  the  top.  If  the  wound  is  left  exposed  to  the  sun 
and  wind  during  the  time  required  for  healing,  its  surface 
invites  decay.  To  prevent  this  we  must  protect  the  wound 
at  once  by  applying  shellac  or  coal  tar  to  its  entire  surface. 
The  use  of  grafting  wax  or  other  thick  coatings-  for  such  a 
purpose  is  not  recommended,  as  they  are  likely  to  be  cracked 
or  pushed  off  by  the  growth  of  the  new  bark  and  thus  leave 
the  wood  comparatively  unprotected.  A  solution  of  shellac 
and  alcohol,  such  as  is  commonly  used  by  painters,  is  an  ex- 
cellent wood  preservative,  as  it  closes  the  wound,  prevents 


178  THE  GYPSY  MOTH. 

the  exudation  of  crude  sap,  commonly  called  "bleeding,"  and 
is  not  open  to  the  objection  which  applies  to  grafting  wax. 
Paint  is  often  used.  Thick  mineral  paint  mixed  with  linseed 
oil  has  given  satisfactory  results  at  the  Massachusetts  Agri- 
cultural College  at  Amherst,  and  is  recommended  by  Prof. 
S.  T.  Maynard.  Coal  tar  has  been  long  used  in  Europe 
as  the  best  substance  known  for  this  purpose.  It  needs 
no  preparation  aside  from  an  occasional  warming  in  cold 
weather,  and  may  be  readily  applied  with  a  painter's  brush. 
This  substance  will  not  injure  the  wood,  but,  on  the  con- 
trary, is  one  of  the  most  perfect  wood  preservatives  known. 
If  pruning  is  done  with  discretion  at  the  right  season, 
the  trunk  being  not  already  decayed,  and  if  the  tar  is 
applied  at  once  on  the  removal  of  the  branch,  the  wood 
will  remain  sound,  and,  except  in  the  case  of  very  old 
and  feeble  trees,  the  new  growth  will  in  time  cover  the 
wound.  Decay  may  be  prevented  or  delayed  even  in  old 
trees  by  such  treatment.  Coal  tar  should  be  used  with  some 
caution  on  cherry  and  plum  trees,  as  it  may  injure  the  tree 
if  applied  to  the  bark.  Wounds  on  the  maple  and  elm, 
which  often  "bleed, "may  need  more  than  one  application 
of  coal  tar  to  stop  the  "bleeding."  In  such  cases  the  first 
coat  of  tar  should  be  well  rubbed  oif  before  the  second 
application. 

The  two  most  essential  rules  in  regard  to  removing  limbs 
are  followed  in  the  pruning  done  in  the  gypsy-moth  work. 
Although  known  and  practised  in  this  country  at  the  begin- 
ning of  the  present  century,  they  have  been  ignored  by  most 
American  writers  on  tree  pruning.  Yet  Wm.  Coxe  of 
Burlington,  N.  J.,  wrote  in  1817  :  — 

In  cutting  off  a  branch,  it  should  be  done  as  close  as  possible, 
never  leaving  a  stump,  for  the  bark  cannot  grow  over  it,  and 
disease  in  the  wood  will  inevitably  follow.  If  the  wound  produced 
by  the  separation  be  very  large,  cover  it  with  tar  or  thick  paint.* 

The  principles  of  pruning  were  ably  set  forth  in  1861  by 
De  Courval,  as  practised  with  perfect  success  for  more  than 
forty  years  in  the  forest  of  his  vast  estate  of  Pinon  (Aisne), 

*  Coxe  on  "  Fruit  Trees,"  1817,  page  41. 


KULES  FOE  PRUNING.  179 

France.  Later  in  1864  the  Baron  Des  Cars  published  an 
able  treatise,  describing  a  thorough,  practical  system  of 
forest-tree  pruning,  based  on  the  principles  laid  down  by 
De  Courval.  The  American  edition  of  this  work  (trans- 
lated from  the  seventh  French  edition)  with  an  introduc- 
tion by  Dr.  Chas.  S.  Sargent,  professor  of  arboriculture  in 
Harvard  University,  is  the  most  comprehensive  work  on  this 
subject  that  has  ever  appeared  in  the  English  language.* 
The  publication  of  the  American  edition  of  this  work  was 
made  possible  by  the  trustees  of  the  Massachusetts  Society 
for  the  Promotion  of  Agriculture,  an  old  and  honored  asso- 
ciation, which  has  done  much  for  the  improvement  of  agri- 
culture in  this  Commonwealth.  The  book  should  be  in  the 
hands  of  every  person  who  has  the  care  of  trees. 

Season  for  Pruning.  —  Writers  on  horticulture  differ  as 
to  the  best  season  for  pruning.  Each  urges  the  advantages 
of  pruning  at  certain  seasons  to  increase  wood  growth  or 
the  development  of  fruit.  Objections  are  frequently  made 
to  pruning  in  the  winter,  on  account  of  real  or  supposed 
danger  to  the  tree  from  exposing  large  wounds  to  the  extreme 
cold.  Similar  objections  are  sometimes  urged  to  pruning  in 
the  early  spring  and  late  fall,  when  the  newly  cut  surfaces 
are  exposed  to  the  influence  of  sudden  and  severe  frosts. 
It  is  frequently  said  by  orchardists  that  if  a  tree  is  pruned 
in  the  spring,  when  the  sap  is  flowing  copiously,  and  the 
crude  sap  is  allowed  to  flow  down  from  the  wound,  it  will 
poison  the  bark  below  and  produce  decay  of  the  trunk  of 
the  tree. 

Such  examinations  as  we  have  been  able  to  make  of  the 
results  of  spring  pruning  indicate  that  the  injury  is  due  to 
entirely  different  causes,  viz.,  the  crushing  of  the  bark  and 
consequent  killing  of  the  cambium  layer  at  the  base  of  the 
wound  or  the  separation  of  the  bark  from  the  trunk.  Such 
injuries  are  likely  to  occur  unless  great  care  is  used  in  prun- 
ing. The  danger  of  a  separation  of  the  bark  from  the  trunk 
below  the  wound  and  the  consequent  running  of  the  crude 
sap  into  the  cavity  thus  formed  is  always  greatest  during  the 

*  "  A  treatise  on  pruning  forest  and  ornamental  trees,"  by  A.  Des  Cars,  translated 
from  the  seventh  French  edition,  with  an  introduction  by  Dr.  Chas.  S.  Sargent. 
Boston,  1884. 


180  THE   GYPSY  MOTH. 

time  of  the  year  when  the  bark  peels  most  readily.  In  ex- 
planation of  this,  we  cannot  do  better  than  to  quote  Prof.  R. 
Hartig  of  the  University  of  Munich,  whose  pathological  work 
is  a  model  of  thoroughness  and  scientific  accuracy  :  — 

At  the  time  when  the  cambium  is  active,  it  is  quite  impossible 
to  prevent  the  cortex  being  loosened,  the  friction  of  the  saw  being 
sufficient  to  account  for  it.  But  the  main  cause  is  to  be  traced  to 
the  fact  that,  in  order  to  prevent  the  cortex  being  torn  off,  a  cut  is 
first  of  all  made  underneath,  and  during  the  sinking  of  the  branch 
the  lower  edge  of  the  wound  is  subjected  to  severe  pressure.  The 
cortex  of  the  lower  edge  of  the  wound  forms  a  pivot  round  which 
the  sinking  branch  turns,  and,  although  the  effects  may  not  be 
immediately  visible,  still,  the  crushing  and  tearing  at  that  point 
kills  the  cambium  for  an  inch  or  two  from  the  edge  of  the  wound. 
Of  course  in  such  a  case  the  new  growth  —  namely,  the  callus  —  is 
not  formed  at  the  edge  of  the  wound,  but  at  a  considerable  dis- 
tance from  it,  where  it  is  covered  by  the  cortex.  The  result  is 
that  the  cortex,  which  was  originally  in  intimate  contact  with  the 
wood,  becomes  detached,  so  that  a  cavity  is  formed  beneath  the 
wound  between  the  wood  and  the  dead  tissues.  This  cavity  acts 
like  a  gutter  to  catch  the  rain-water  that  flows  over  the  surface  of 
the  wound,  as  well  as  all  the  organisms  that  it  may  contain.  This 
forms  a  specially  suitable  place  for  the  germination  of  the  spores 
or  parasitic  fungi,  and  it  is  from  here  that  water  containing  the 
soluble  products  of  decomposition  finds  its  way  by  means  of  the 
medullary  rays  into  the  interior  of  the  wood.  This  cavity  is  a 
gutter  in  every  sense  of  the  term,  and  at  the  same  time  the  point 
of  attack  for  fungi.  Even  although  the  surface  of  the  wound  may 
have  been  coated  with  tar  immediately  after  pruning,  this  spot 
remains  unprotected,  and  indeed  it  is  only  formed  after  the  cortex 
has  been  separated  from  the  wood  by  the  advancing  callus.  It  is 
in  fact  the  Achilles'  heel  of  the  branch  wound.  In  pruning,  the 
main  object  must  be  to  prevent  its  formation ;  but  this  is  possible 
only  if  pruning  be  confined  to  autumn  and  winter,  when  growth 
is  at  a  stand-still,  and  when  the  cortex  is  less  liable  to  be  detached 
from  the  wood.  If  one  also  takes  the  precaution  to  support  the 
branch  during  sawing,  and  at  the  moment  of  separation  to  push  it 
clear  of  the  wound,  danger  is  reduced  to  the  minimum.* 


*  "  The  Diseases  of  Trees,"  by  Prof.  R.  Hartig,  pages  255-257.    English  edition  by 
Dr.  H.  Marshall  Ward,  London,  1894. 


SEASON  FOR  PRUNING.  181 

An  examination  of  injurious  results  of  spring  and  summer 
pruning  indicates  that  the  injury  sometimes  extends  down- 
ward and  serious  harm  is  done. 

There  is  a  danger  from  the  running  of  sap  which  occurs 
when  pruning  is  done  in  spring  or  summer,  aside  from  any 
possible  harm  resulting  from  the  drain  on  the  vitality  of  the 
tree.  Warmth  and  dampness  are  particularly  favorable  for 
the  germination  of  parasitic  fungi  and  the  progress  of  decay. 
Though  decay  may  occur  without  the  presence  of  these 
organisms,  its  progress  is  more  rapid  when  they  are  pres- 
ent. Therefore,  wounds  which  are  constantly  kept  wet  in 
warm  weather  by  the  flow  of  crude  sap  are  most  likely  to 
decay. 

There  are  reasons  also  why  pruning  in  summer  is  likely 
to  be  weakening  to  the  tree  :  — 

If  the  term,  winter  pruning,  is  given  to  any  removal  of  shoots 
during  the  resting  period  of  a  woody  plant,  we  may  say  generally 
that  winter  pruning  is  strengthening,  while  summer  pruning  is 
weakening. 

If  any  portion  of  the  shoot  system  is  taken  away  after  it  has 
passed  through  one  summer,  the  structure  and  activity  of  the 
root  system  —  that  is,  its  power  of  absorption  and  of  forcing  up 
water — is  such  that  it  can  nourish  all  the  branches.  At  the 
beginning  of  the  next  period  of  activity,  by  cutting  away  some 
branches  the  water-consuming  area  is  diminished.  The  same 
amount  of  pressure  has  therefore  a  reduced  field  of  action, 
and  consequently  the  effect  on  the  remaining  branches  must  be 
increased. 

By  pruning  in  the  summer  we  remove  soft  shoots  with  only 
recently  developed  leaves.  The  latter  have  yet  their  chief  work 
to  perform ;  for  at  the  commencement  they  are  developed  at  the 
cost  of  the  reserve  material  which  is  stored  up  in  the  branch,  then 
comes  a  period  at  which  the  young  leaf  requires  all  the  substance 
it  assimilates  from  without  for  its  own  growth,  and  only  after 
its  full  development  does  it  begin  to  work  for  the  benefit  of 
the  branch.  If,  therefore,  a  soft  shoot  is  taken  away,  the  older 
portions  of  the  branch  are  robbed  of  the  materials  which  were 
used  in  the  unfolding  of  the  leaves,  without  receiving  anything  in 
return  from  the  leaves  they  have  developed.  This  causes,  there- 
fore, a  loss  to  the  general  economy  of  the  plant ;  but,  with  the 


182  THE   GYPSY  MOTH. 

increased  productiveness  of  our  cultivated  plants,  such  a  slight 
weakening  may  be  overlooked,  if  any  other  special  advantage  is 
gained.* 

Tarring  the  wounds  gives  the  most  satisfactory  result  when 
pruning  is  done  late  in  the  autumn  or  in  winter,  for  it  is 
then  that  the  tar  is  best  absorbed  by  the  surface  of  the 
wound.  When  branches  are  cut  off  in  spring  or  summer, 
the  tar  fails  to  penetrate  the  surface  of  the  wound  because 
of  the  flowing  sap,  and  its  thin  superficial  layer  does  not 
prevent  the  cut  from  drying  later.  In  drying,  cracks  are 
formed,  into  which  water  and  the  spores  of  fungi  may  gain 
entrance.  For  this  reason  it  is  often  necessary  to  apply  two 
or  more  coats  of  tar  to  the  wound. 

Having  considered  some  of  the  objections  to  removing 
limbs  in  summer,  it  is  plain  that  the  late  winter  is  the  most 
favorable  time  for  such  pruning  as  is  here  advocated.  There 
is  then  less  exposure  to  extreme  cold  to  be  considered.  It 
is  known  that  certain  trees  have  a  considerable  flow  of  sap 
in  winter.  It  is  said  that  the  Indians  were  accustomed  to 
draw  the  sap  from  the  sugar  maples  in  November,  when 
good  sap  days  frequently  occur,  f  It  may  be  better  to  prune 
such  trees  in  the  spring  or  summer.  The  results  of  pruning 
native  deciduous  and  coniferous  trees  at  different  seasons 
of  the  year  have  never  been  fully  observed  with  scientific 
accuracy,  and  there  is  much  to  be  learned. 

Removal  of  Dead  or  Broken  Branches.  —  Dead  branches 
may  be  removed  at  any  time  of  the  year,  if  proper  precau- 
tions are  taken  to  avoid  injuring  the  bark  or  trunk  of  the 
tree  in  the  operation.  If  these  branches  are  left  upon  the 
tree  until  they  decay  and  drop  off  or  are  torn  away  by 
the  winds,  the  bark  loosens  and  forms  a  harboring  place  for 
the  gypsy  moth  and  certain  other  insects,  which  hide  beneath 
it  and  oviposit  there.  Their  eggs  being  out  of  sight,  they 
hibernate  in  comparative  safety  until  the  following  spring, 
when  the  larvre  hatch  and  attack  the  foliage,  thus  weakening 
the  tree.  If  dead  branches  are  not  removed,  they  are  some- 

»  "A  popular  treatise  on  the  physiology  of  plants,"  by  Dr.  Paul  Sorauer.  English 
edition  by  Prof.  F.  E.  Weiss,  pages  137,  138. 

t  "The  Circulation  of  Sap  in  Plants,"  by  W.  S.  Clark.  Annual  Report  of  the 
Massachusetts  State  Board  of  Agriculture,  1873-74,  page  162. 


REMOVING  DEAD  BRANCHES.  183 

times  broken  off  by  the  wind,  leaving  a  long  stump  project- 
ing from  the  tree.  The  ragged  surface  of  the  break  offers 
perfect  conditions  for  the  beginning  of  decay,  and  the  seams 
of  the  stump  communicate  it  rapidly 
to  the  trunk.  Fig.  17  shows  a  section 
of  a  tree  trunk  bearing  the  broken 
stump  of  a  dead  branch.  The  tree, 
being  vigorous,  has  pushed  forward 
callus  on  the  branch  and  partially 
covered  it  with  new  wood  and  bark. 
This  attempt  at  healing  might  have 
been  successful  had  the  branch  been 
broken  close  to  the  tree ;  but  in  this 
case  the  effort  of  the  tree  to  heal  the  _ 

FIG.  17.    Decaying  branch  left  on 

wound  was  of  no  avail.     The  neglect  the  trunk  of  tree. 

to  remove  these  dead  branches  is  often  indirectly  the  cause 
of  cavities  in  tree  trunks.  When  living  branches  are  broken 
by  the  wind,  heavy  loads  of  fruit  or  other  causes,  the  stumps 
should  be  removed.  Such  ragged  and  broken  snags  offer 
points  of  attachment  for  parasitic  fungi ;  and  if  the  break 
occurs  in  summer,  when  the  sap  is  flowing,  the  conditions 
are  particularly  favorable  for  the  propagation  of  these  fungi, 
and  the  extension  of  wound  rot. 

The  decay  of  a  tree  trunk  resulting  from  improper  pruning 
and  the  neglect  to  remove  broken  branches  is  shown  in  Fig. 
18.  Such  rotting  away  of  the  wood  of  the  tree  as  is  shown 
here  will  not  occur  immediately,  but  is 
the  result  which  will  inevitably,  in  the 
course  of  years,  follow  such  a  policy.  If 
pruning  is  begun  on  the  young  fruit  tree 
by  nipping  off  buds  and  directing  shoots 
so  as  to  form  a  symmetrical  head,  and  is 
carried  on  with  good  judgment  as  the  tree 
grows,  there  will  be  no  need  of  the  ampu- 
tation of  large  limbs,  except  such  as  are 
broken  by  accident  or  die  from  other  causes. 

Amputations  of  the  large  lower  branches       result  of  neglect  and 

f    ,  n  .  bad  pruning. 

of  shade  trees  are  often  necessary  in  pruning 
for  beauty  and  utility.    In  orchards  bad  pruning  often  neces- 
sitates later  the  removal  of  large,  decaying  hollow  limbs,  lest 


184  THE   GYPSY  MOTH. 

they  break  down  and  split  off  a  portion  of  the  trunk,  which 
in  such  case  is  frequently  hollow.  The  removal  of  such 
limbs  in  time  may  prevent  injury  to  the  trunk.  These  am- 
putations when  necessary  are  merely  a  question  of  surgery  ; 
and  if  they  are  performed  at  the  right  season  and  in  the 
proper  manner,  and  the  wound  is  properly  treated,  there  is 
little  danger  of  injury  to  an  otherwise  sound  tree.  Where 
injury  to  such  a  tree  results  from  the  process,  it  is  usually 
from  ignorance  of  correct  methods  or  carelessness  in  their 
use.  Still,  it  is  well  to  bear  in  mind  that  when  a  surgical 
operation  is  to  be  performed,  the  result  depends  not  only  on 
the  skill  of  the  operator  but  also  on  the  age  and  vigor  of  the 
subject. 

The  death  of  old  decaying  trees  is  sometimes  hastened  by 
the  amputation  of  large  and  hollow  branches.  The  shock 
caused  by  the  removal  of  several  large  branches,  together 
with  the  reduction  of  leaf  surface,  which  makes  it  difficult 
for  the  tree  to  heal  the  wounds,  will  often  kill  such  trees.* 
The  proper  method  for  treating  the  cavities  of  such  trees  will 
be  spoken  of  later. 

Removing  Large  Limbs.  —  In  this  process  great  caution 
must  be  exercised :  (1)  not  to  injure  the  tree  by  the  unneces- 
sary removal  of  too  many  large  branches  in  one  season  ;  (2) 
to  avoid  injury  of  the  tree  by  the  breaking  down  or  falling 
of  the  branch;  (3)  to  guard  against  accidents  to  work- 
men. The  old  rule  for  removing  large  branches  was  to 
cut  the  stump  across  its  diameter  near  its  base,  never  mak- 
ing a  cut  larger  than  the  diameter  of  the  branch.  This 
practice  has  already  been  shown  to  be  pernicious,  as  the 
tree  has  great  difficulty  in  covering  the  lower  part  of  the 
wound  with  a  new  growth  of  bark.  Where  a  large  limb 
is  removed  in  this  manner,  the  lower  part  of  the  stump 
never  becomes  entirely  covered,  and  finally  decays.  In  saw- 
ing off  a  branch  the  first  cut  should  never  be  made  from 
above,  as  the  limb  is  likely  to  split  and  tear  away  from 
the  trunk.  The  result  of  such  an  accident  as  is  shown  in 


*  If  an  old  tree  with  sound  trunk  whose  branches  appear  to  be  dying  is  "  headed 
down"  by  the  removal  of  most  or  all  of  its  large  branches,  it  may  revive,  throw  out 
shoots  and  form  a  smaller  and  more  vigorous  head. 


REMOVING  LARGE  LIMBS. 


185 


Fig.  19  may  prove  very  serious  to  a  tree.     Whenever  it  is 

necessary  to  amputate  a  large  or  long  branch,  a  cut  should 

be   made   from  the   under  side  of  the 

branch,  at  a  distance  of  two  or  three  feet 

from  the  trunk,  and  should  extend  half 

way  through  its  diameter,  as  in  Fig.  20, 

line  A ;  another  cut,  B,  should  then  be 

made  farther  out,  extending  down  into 

the  branch  until  it  falls.     The  first  cut 

will  prevent   the   limb    from  breaking  FIG.  19.  Limb  breaking  down 

n         TJ.A-  a?         n  j-i_     i        i    £  from  cut  wrongly  made. 

and  splitting  on  and  the  bark  from  tear- 
ing down  on  the  tree.  The  stump  may  then  be  removed 
close  to  the  trunk  on  the  line  C,  cutting  first  from  below, 
and  supporting  the  stump  so  that  crushing  or  tearing  of 
the  bark  may  again  be  avoided.  This 
method  will  prevent  injury  to  the  tree 
and  guard  against  serious  accidents  which 
sometimes  occur  when  the  limb  is  first 
cut  too  close  to  the  tree.  .  In  such  cases 
the  outer  end  of  the  branch  striking  the 
ground  has  sometimes  caused  the  inner 
FIG.  20.  The  proper  method  end  to  rebound  and  strike  or  throw  down 

of  removing  a  large  limb.      the  workman>       Whatever  method  IS  eiU- 

ployed,  the  wound  should  be  made  perfectly  smooth  and  even 
with  the  outline  of  the  trunk  by  cutting  or  planing  its  sur- 
face, which  should  then  be  immediately 
covered  with  coal  tar.*  On  fruit  trees, 
however,  it  is  well  never  to  remove  a 
large  excrescence  or  shoulder  (such  as  is 
sometimes  formed  at  the  base  of  a  limb) 
if  the  wood  is  sound,  but  to  cut  the 
limb  at  its  junction  with  the  shoulder. 
Large  wounds  are  often  made  in  the 
tree  trunk  by  the  teeth  of  horses,  the 
breaking  down  of  large  limbs  or  in  other 
accidental  ways.  When  such  an  acci-  the  breaking  of  a  large  nmb. 
dent  occurs  as  is  shown  in  Fig.  21,  it  should  receive  imme- 

*  If  the  roughened  surface  left  by  a  saw-cut  is  smoothed,  it  lessens  the  danger 
of  decay ;  and  if  the  edges  of  the  wound  are  trimmed  down  to  the  outline  of  the 
tree,  the  wound  is  more  readily  covered  by  the  occluding  callus. 


A  trunk  injured  by 


186 


THE   GYPSY  MOTH. 


diate  attention.  It  is  necessary  to  cut  away  the  stump 
which  is  left  and  to  remove  as  much  of  the  wood  as  will  be 
required  to  make  an  even  surface ;  also  to  cut  away  all  the 
bark  which  has  been  loosened  below  the  wound.  Otherwise 
such  a  wound  will  in  time  present  an  appearance  similar 
to  that  shown  in  Fig.  22,  and  the  injury  may  continue  to 
extend.  If  such  wounds  are  not  immediately  treated  and 
covered  with  coal  tar,  their  inner  surface  often 
becomes  decayed,  threatening  the  life  of  the 
tree.  If  the  decayed  wood  is  carefully  cut 
away  and  the  exposed  surface  thoroughly 
covered  with  coal  tar,  the  tree  will  remain 
healthy.  Though  the  new  wood  and  bark 
may  never  entirely  cover  the  wound,  there 
will  be  no  further  decay. 
FIG.  22.  A  cavity  A  cavity  treated  in  the  manner  above  de- 

caused  by  the  tearing  .  . 

away  of  a  large  limb,  scribed  is  shown  in  tig.  23.  Decay  has  been 
stopped,  and  the  new  bark  and  wood  have  entirely  covered 
the  edges  of  the  wound,  leaving  the  tree  in  a  healthy  condi- 
tion. The  directions  given  by  Des  Cars 
for  the  use  of  coal  tar  on  trees  are  so  ad- 
mirably stated  that  we  give  an  extract 
from  them  :  — 


Coal  tar  has  remarkable  preservative  prop- 
erties, and  may  be  used  with  equal  advantage 
on  living  and  dead  wood.     A  single  application 
PIG.  23*  A  cavity  properly  without  penetrating  deeper  than  ordinary  paint 
treated;  decay  arrested  forms  an  impervious  coating  to  the  wood  cells, 

and  healing  begun.  .  .  ..       .  ,  .  . 

which  would  without  such  covering,  under  ex- 
ternal influences,  soon  become  channels  of  decay.  This  simple 
application,  then,  produces  a  sort  of  instantaneous  cauterization, 
and  preserves  from  decay  wounds  caused  either  in  pruning  or  by 
accident.  The  odor  of  coal  tar  drives  away  insects,  or  prevents 
them,  by  complete  adherence  to  the  wood,  from  injuring  it.  After 
long  and  expensive  experiments  the  director  of  the  parks  of  the 
city  of  Paris  finally,  in  1863,  adopted  coal  tar  in  preference  to 
other  preparations  used  for  covering  tree  wounds,  as  may  be  seen 
in  all  the  principal  streets  of  the  capital.  .  .  . 

One  coat  of  coal  tar  is  sufficient  for  wounds  of  ordinary  size ; 
but  when  they  are  exceptionally  large,  a  second  coat  may  after 
a  few  years  be  well  applied.  In  warm  countries,  like  the  south 


TREATING  HOLLOW  TREES.  187 

of  France,  the  great  heat  of  summer  renders  coal  tar  so  liquid  that 
it  is  impossible  to  properly  treat  wounds  made  at  that  season. 
In  such  cases  another  coat  should  be  applied  during  the  following 
winter.* 

Removing  Shoots  and  Suckers. — Many  street  trees,  espe- 
cially elms,  which  have  suffered  from  the  effects  of  bad 
pruning,  send  forth  shoots  or  suckers  from  many  points  of 
the  trunk.  These  shoots  are  believed  to  be  detrimental 
rather  than  beneficial  to  the  tree,  impairing  the  development 
of  its  top  and  larger  branches.  So  long  as  suckers  are 
allowed  to  remain,  many  of  the  gypsy-moth  caterpillars 
will  seek  shelter  among  them  during  the  day  in  preference 
to  going  to  the  burlap.  If  suckers  are  carefully  removed, 
no  injury  to  the  tree  will  result. 

Treating  Hollow  Trees.  —  When  the  trunks  and  larger  limbs 
of  trees  are  riddled  with  holes  caused  by  neglect  or  bad 
pruning,  another  mode  of  treatment  becomes  necessary. 
Thousands  of  gypsy  caterpillars  which  feed  upon  the  foliage 
at  night  will  retire  through  the  holes  to  the  interior  of 
the  hollow  trunks  and  branches,  where  they  secrete  them- 
selves during  the  day,  emerging  at  night  to  continue  their 
destructive  work  under  cover  of  the  darkness.  The  clos- 
ing of  such  cavities  by  filling,  covering  or  sealing  them  is 
an  important  auxiliary  to  the  other  means  of  extermination. 
It  prevents  the  caterpillars  from  hiding  and  the  moths 
from  ovipositing  within  the  hollow  trunks  and  branches, 
and  drives  them  to  the  burlap  for  shelter.  If  the  holes 
are  carefully  covered  in  the  winter,  many  eggs  are  en- 
closed within.  When  they  hatch  in  the  spring,  the  young 
caterpillars  are  prevented  from  leaving  their  hiding-places 
and  are  thus  buried  alive,  as  it  were,  in  the  tree  trunks.  This 
work  must  be  very  thoroughly  done  to  prevent  the  escape 
of  the  minute,  newly  hatched  caterpillars. 

During  the  work  of  the  first  gypsy  moth  commission 
many  holes  were  filled  with  hydraulic  cement.  If  the  hole 
was  large,  it  was  packed  with  stones  and  a  coating  of  cement 
put  on  the  face  of  this  filling  at  the  mouth  of  the  hole.  If 
the  hole  treated  was  in  a  large  and  otherwise  sound  trunk, 

*  "  Tree  Pruning,"  by  A.  Des  Cars,  pages  58  and  59. 


188 


THE   GYPSY  MOTH. 


the  cement,  provided  it  was  properly  mixed  and  applied, 
remained  intact  for  years.  Small  holes  surrounded  by  sound 
wood  were  also  filled  to  advantage  in  this  manner.  The 
cement  may  be  held  effectively  if  laid  on  a  strong  iron  wire 
netting  nailed  across  and  just  within  the  mouth  of  the  hole. 
Whenever  cement  is  used  on  growing  trees,  it  'should  be 
faced  up  within  the  growth  of  new  bark  and 
wood,  so  that  the  latter  may  grow  over  and 
hold  it  tightly.  (See  Fig.  24.)  When  the 
callus  has  already  formed  on  the  edge  of 
the  cavity,  it  should  be  cut  away.  This 
cutting  will  stimulate  new  growth,  and  if 
the  cement  is  properly  faced  up  within 
the  mouth  of  the  cavity,  the  callus  will 
eventually  cover  it.  If  the  hole  is  so  filled 
that  the  cement  laps  over  the  ed^e  upon 

FIG.  24.    Cemented  cavity. 

the  bark,  it  is  likely  to  prove  worse  than 
useless,  as  the  growing  bark  beneath  the  cement  will  throw 
it  off  from  the  tree,  leaving  a  space  as  a  hiding-place  for  the 
caterpillars.  Hard  cement  must  be  carefully  applied  by  an 
experienced  man,  otherwise  it  is  likely  to  prove  worthless, 
and  by  crumbling  and  cracking  leave  the  cavity  in  a  worse 
condition  than  before. 

This  cement  cannot  be  used  during  the  colder  months  of 
the  year,  as  the  action  of  the  frost  may  cause  it  to  crack. 
Neither  can  it  be  used  effectively  to  stop  cracks  or  cavities, 
the  sides  of  which  may  be  moved  independently  of  each 
other  by  the  action  of  the  wind  on  the  branches.  Experi- 
ments in  closing  such  cavities  with  plaster  of  Paris,  mineral 
wool,  Purcell's  elastic  cement,  Webster's  elastic 
cement,  Portland  cement  and  Roslindale  cement 
were  made  in  the  winter  of  1891-92.  None  of 
these  materials  gave  satisfactory  results.  Tarred 
burlap  or  canvas  has  been  used  for  this  purpose 
with  some  success.  If  three  thicknesses  of  bur- 
la"p  are  closely  and  strongly  tacked  over  the 
opening  to  a  hollow  in  a  tree  trunk  and  after- 
ward thoroughly  soaked  with  coal  tar  (Fig. 
25)  the  covering  will  remain  intact  and  imper- 
vious to  the  weather  for  several  vears.  Oiled  cloth  will  also 


PLATE  XXXIII.     Pruning  and  scraping  tree 


COVERING  HOLES  IN  TREES.  189 

answer  the  same  purpose.  These  fabrics  are  not  materially 
affected  by  the  movements  of  the  tree,  and  if  well  tarred  are 
not  often  bored  through  by  insects,  as  the  tar  is  repugnant 
to  them. 

In  many  cases  such  cavities  as  are  exposed  by  the  sawing 
off  of  large  hollow  stumps  of  broken  branches  may  be  covered 
to  advantage  with  tin  or  zinc,  which  must  be  tacked  closely 
over  the  cavity  and  afterwards  painted  or  tarred.  (See  Fig. 
26. )  If  these  coverings  are  applied  in  the  win-  fcUJ1 
ter,  it  may  be  necessary  to  use  in  connection  with 
them  some  such  substance  as  the  insect  lime,  in 
order  to  prevent  the  escape  of  the  young  cater- 
pillars in  the  spring.  This  substance  may  be 
smeared  around  the  edge  of  the  tin  or  burlap  in 
such  a  manner  as  to  close  every  crevice  commu- 
nicating with  the  cavity.  It  has  also  been  used 
to  stop  small  holes  in  trees,  and  will  answer  the  Tinned  cavity' 
purpose  temporarily,  but  it  must  be  occasionally  smoothed 
over,  as  it  shrinks  and  cracks  in  a  short  time. 

Scraping  Trees  and  Removing  Loosened  Bark. 

Scraping  the  loose  outer  bark  from  old  trees  facilitates 
the  discovery  of  th^p  eggs,  larvae  and  pupse  of  the  gypsy 
moth.  Such  scraping  leaves  the  surface  of  the  trunk  and 
larger  branches  in  a  comparatively  smooth  condition,  and 
deprive*  the  caterpillars  of  their  places  of  refuge,  causing 
them  to  crawl  down  and  seek  shelter  under  the  burlaps. 

If  in  dealing  with  fruit  trees  the  loose  bark  only  is  scraped 
off  and  burned,  the  main  object  is  accomplished.  Such  scrap- 
ing benefits  orchard  trees  by  the  removal  of  mosses  and 
lichens  and  the  eggs  and  hibernating  forms  of  injurious 
insects. 

An  implement  modelled  after  the  scuffle  hoe  is  useful  for 
this  work.  (Fig.  27 .)  Its  blade  being  double-edged,  it  may 
be  used  with  both  the  upward  and  downward  motion,  and  by 
means  of  a  long  handle  the  trunk  and  branches  of  the  fruit 
trees  may  be  reached  to  a  height  of  from  twelve  to  eighteen 
feet  from  the  ground.  The  ordinary  "three-cornered" 
scraper  is  also  much  used.  It  is  believed  that  this  loose 
outer  bark  forms  a  protection  to  the  tree  from  the  cold  of 


190  THE   GYPSY  MOTH. 

winter.  Objections  to  its  removal  based  on  this  belief  are 
obviated  by  scraping  in  the  spring  before  the  opening  of 
the  leaves,  when  the  tree  no  longer  needs  protection  against 
the  cold.  If  the  loose  bark  of  apple  trees  is  scraped  off 
about  April  15  and  caught  upon  cloths  spread  beneath  the 
trees  and  the  scrapings  afterward  burned,  many  injurious 
insects  are  likely  to  be  destroyed. 


FIG.  27.    Long  handled  scraper.  FIG.  28.    Bark  shave. 

If  we  go  further,  and  without  cutting  too  deeply  remove 
some  of  the  outer  bark,  double  benefit  to  the  tree  ensues.* 

Its  growth  is  stimulated,  a  great  flow  of  crude  sap  occurs, 
a  luxuriant  growth  of  foliage  is  thrown  out  and  an  unusual 
supply  of  elaborated  sap  for  the  upbuilding  of  the  tree  is 
returned  from  the  foliage  and  flows  into  the  liber  or  inner 
lining  of  the  bark,  killing  or  driving  away  the  bark  borers 
(scolytidm) .  These  beetles  are  among  the  most  dangerous 
enemies  of  trees.  For  bark  cutting  a  shave  (Fig.  28)  in- 
vented by  Mr.  G.  W.  McKee,  one  of  the  special  inspectors 
employed  by  the  Board,  has  been  found  very  effective. 

Dr.  Packard  says  that  perhaps  the  best  method  of  pre- 
venting or  stopping  the  work  of  bark  beetles  is  that  of  a 

»  Elms  which  have  had  the  outer  bark  removed  in  this  manner  in  November  have 
developed  an  unusually  vigorous  growth  of  dark  green  foliage  in  the  ensuing  sum- 
mer. Trees  treated  in  this  manner  have  shown  great  vigor  also  in  healing  wounda 
oil  their  trunks. 


SCRAPING  TREES.  191 

Frenchman,  M.Robert,  as  described  in  the  ''Gardener's 
Chronicle  "  and  referred  to  by  Miss  Ormerod.  He  gives  the 
quotation  from  Miss  Ormerod  as  follows  :  — 

The  best  remedy  appears  to  be  that  adopted  with  great  success 
in  France  by  M.  Robert,  after  careful  observation  of  the  circum- 
stances which  stopped  the  operations  of  the  female  beetle  when 
gnawing  her  gallery  for  egg  laying,  or  which  disagreed  with  or 
destroyed  the  maggots,  and  is  based  in  part  on  similar  observa- 
tions of  the  effect  of  flow  of  sap  to  those  noticed  in  England  by 
Dr.  Chapman. 

It  appeared  on  examination  that  the  grubs  died  if  they  were  not 
well  protected  from  the  drying  action  of  the  air ;  on  the  other 
hand,  if  there  was  a  very  large  amount  of  sap  in  the  vegetable 
tissues  that  they  fed  on,  this  also  killed  them  ;  and  it  was  observed 
that  when  the  female  was  boring  through  the  bark  if  a  flow  of  sap 
took  place  she  abandoned  the  spot  and  went  elsewhere.  It  was 
also  noticed  that  the  attack  (that  is,  the  boring  of  the  galleries 
which  separates  much  of  the  bark  from  the  wood)  is  usually  under 
thick  old  bark,  such  as  that  of  old  elm  trunks,  rather  than  under 
the  thinner  bark  of  the  branches.  Working  on  these  observations, 
M.  Robert  had  strips  of  about  two  inches  wide  cut  out  of  the  bark 
from  the  large  boughs  down  the  trunk  to  the  ground,  and  it  was 
found  that  where  the  young  bark  pressed  forward  to  heal  the 
wound  and  a  vigorous  flow  of  sap  took  place  many  of  the  maggots 
near  it  were  killed,  the  bark  which  had  not  been  entirely  under- 
mined was  consolidated  and  the  health  of  the  tree  was  improved. 

Working  on  from  this,  M.  Robert  tried  the  more  extended 
treatment  of  paring  off  the  outer  bark,  a  practice  much  used  in 
Normandy  and  sometimes  in  England  for  restoring  vigor  of  growth 
to  bark-bound  apple  trees,  and  noted  by  Andrew  Knight  as  giving 
a  great  stimulus  to  vegetation.  M.  Robert  had  the  whole  of  the 
rough  outer  bark  removed  from  the  elm  (this  may  be  done  con- 
veniently by  a  scraping  knife  shaped  like  a  spoke  shave).  This 
operation  caused  a  great  flow  of  sap  in  the  inner  lining  of  the  bark 
(the  liber),  and  the  grubs  of  the  Scolytus  beetle  were  found  in 
almost  all  cases  to  perish  shortly  after.  Whether  this  occurred 
from  the  altered  sap  disagreeing  with  them,  or  from  the  greater 
amount  of  moisture  around  them,  or  from  the  maggots  being  more 
exposed  to  atmospheric  changes,  or  any  other  cause,  was  not 
ascertained,  but  the  trees  that  were  experimented  on  were  cleared 
of  the  maggots.  The  treatment  was  applied  on  a  large  scale,  and 
the  barked  trees  were  found,  after  examination  by  the  commis- 
sioners of  the  institute  at  two  different  periods,  to  be  in  more 


192  THE  GYPSY  MOTH. 

vigorous  health  than  the  neighboring  ones  of  which  the  bark  was 
untouched.  More  than  two  thousand  elms  were  thus  treated. 

This  account  is  abridged  from  the  leading  article  in  the  "  Gar. 
deuer's  Chronicle  and  Agricultural  Gazette"  for  April  29,  1848, 
and  the  method  is  well  worth  trying  in  our  public  and  private 
parks.  It  is  not  expensive ;  the  principle  on  which  it  acts  as 
regards  vegetable  growth  is  a  well-known  one,  and  as  regards 
insect  health  it  is  also  well  known  that  a  sudden  flow  of  the  sap 
that  they  feed  on,  or  a  sudden  increase  of  moisture  around  them, 
is  very  productive  of  unhealthfulness  or  of  fatal  diarrhoea  to 
vegetable-feeding  grubs. 

A  somewhat  similar  process  was  tried  by  the  Botanic  Society,  in 
1842,  on  trees  infested  by  the  Scolytus  destructor  in  the  belt  of 
elms  encircling  their  garden  in  the  Regents'  Park,  London.  "It 
consists  in  divesting  the  tree  of  its  rough  outer  bark,  being  careful 
at  the  infested  parts  to  go  deep  enough  to  destroy  the  young  larvae, 
and  dressing  with  the  usual  mixture  of  lime  and  cow  dung."  This 
operation  was  found  very  successful,  and  details  with  illustrations 
were  given  in  a  paper  read  in  1848  before  the  Botanic  Society.* 

No  injury  to  trees  which  have  been  scraped  in  the  course 
of  the  work  on  the  gypsy  moth  has  been  observed,  although 
this  practice  has  been  continued  for  three  years  and  more  than 
nine  thousand  trees  have  been  scraped.  Apple  trees  and  elm 
trees  treated  in  this  way  have  shown  an  immediate  increase 
of  foliage  area  and  growth,  presenting  a  marked  contrast  to 
trees  near  by  which  have  been  left  untreated.  Whether  a  re- 
action will  set  in  in  future  years  remains  to  be  seen.  As  yet 
no  serious  reactionary  effect  has  been  noted.  Trees  which 
have  been  scraped  have  exhibited  remarkable  vigor  in  healing 
wounds.  In  the  gypsy-moth  work  large  elms  are  frequently 
met  with  which  cannot  be  cleared  of  the  moth  without  shav- 
ing off  their  outer  bark.  This  bark  often  overgrows  small 
cavities  in  the  trunk  in  such  a  manner  that  hiding-places  for 
the  moth  are  formed  which  it  is  impossible  to  discover  until 
the  rougher  portion  of  the  outer  bark  has  been  removed. 
While  that  is  being  done,  it  is  not  difficult  to  expose  these 
hiding-places  and  to  destroy  any  form  of  the  moth  found 
within. 

*  Fifth  report  of  the  United  States  Entomological  Commission,  1886-90,  pages  31, 32. 


BUKNING  KUBBISH  HEAPS.  193 

The  Destruction  of  Rubbish. 

The  gypsy  moth,  like  many  other  insects,  shows  a  liking 
for  a  rubbish  pile.  Brush  heaps,  old  stone  walls  and  fences 
overgrown  with  bushes  and  vines,  dumping  grounds,  old 
piles  of  lumber,  tin  cans,  rags,  paper  and  other  debris  all 
furnish  many  hiding-places  for  the  caterpillars,  retreats  for 
pupating  and  places  where  the  moth  can  deposit  its  eggs. 

It  is  remarkable  how  many  absolutely  filthy  rubbish  heaps 
accumulate  in  the  back  yards  of  some  tenement-houses. 
These  deposits  of  rubbish  are  especially  noticeable  in  certain 
districts  of  the  larger  towns  and  smaller  cities.  Not  only 
are  all  sorts  of  waste  material  from  all  parts  of  the  house 
from  cellar  to  garret  thrown  into  the  back  yard,  but  refuse 
from  the  kitchen  is  also  frequently  deposited  there,  together 
with  a  collection  of  empty  but  unclean  cans,  such  as  are  orig- 
inally used  for  "  canned  goods."  Old  shoes,  broken  bottles 
and  earthen  ware,  cast-off  articles  of  apparel,  corn  husks  and 
the  withered  tops  of  vegetables  in  all  stages  of  decay,  bones, 
fish  heads,  lobster  and  oyster  shells  are  also  common  con- 
stituents of  these  rubbish  piles.  Such  heaps  of  rubbish, 
often  overgrown  with  weeds  and  bushes,  would  form  an  in- 
structive spectacle  for  local  boards  of  health.*  Even  the 
grounds  of  the  wealthy  are  not  always  exempt  from  accumu- 
lations of  rubbish,  which  may  be  found  occasionally  about 
the  corners  of  back  fences  or  in  the  rear  of  stables. 

Amid  such  associations  the  gypsy  moth  delights  to  dwell. 
In  the  many  places  of  shelter  oifered  by  such  rubbish  heaps 
the  larvae  can  safely  hide  during  the  day,  sallying  forth  at 
dusk  to  destroy  the  foliage  in  the  vicinity. 

One  of  the  first  steps,  then,  toward  exterminating  the 
gypsy  moth  from  any  locality  is  to  clear  up  the  ground; 
burn  rubbish,  old  lumber,  wood,  brush,  rags  and  dead  leaves ; 
bury  or  melt  up  old  tin  cans ;  tear  down  or  remove  stone 
walls  and  old  fences ;  and  leave  the  premises  as  clean  as  pos- 
sible. Cremation  is  a  cleansing  process ;  bonfires  mark  the 
progress  of  civilization.  Such  work  will  not  only  aid  in 


*    There  has  been  much  improvement  in  respect  to  the  accumulation  of  rubbish  in 
yards  in  our  cities  and  large  towns  since  the  slight  cholera  scare  of  1893. 


194  THE   GYPSY  MOTH. 

disposing  of  the  moth  but  will  remove  harboring  places 
for  other  insects  and  render  the  locality  more  healthful  and 
wholesome.  The  agents  of  the  Board  of  Agriculture  have 
found  it  necessary  to  remove,  burn  or  bury  many  of  these 
accumulations  of  d&bris  in  order  to  secure  the  destruction  of 
the  moth. 

Destroying  Pupce  and  Moths. 

As  the  eggs  of  the  gypsy  moth  hatch  in  the  months  of 
April,  May  and  June,  the  larvae  feed  in  the  latter  part 
of  April  and  during  the  months  of  May,  June,  July  and 
August.  In  July  and  August  all  forms  of  the  moth  may 
be  found  together  in  the  same  locality.  Pupae  and  moths 
are  found  upon  the  same  trees,  under  the  same  burlaps  and 
in  the  same  rubbish  heaps  with  the  larvae ;  therefore  no 
special  measures  are  taken  to  destroy  these  forms  of  the 
insect.  They  are  searched  for  in  all  the  hiding-places  which 
shelter  caterpillars,  and  are  destroyed  by  the  same  means. 
The  white  female  imagoes  are  especially  noticeable  when 
resting  on  the  bark  of  trees.  They  may  be  found  in  July 
and  August,  and,  as  they  do  not  fly,  they  may  be  readily 
captured. 

A  SUMMARY  OF  THE  METHODS  MOST  USEFUL  TO  THE 
FARMER. 

Unless  sufficient  appropriations  are  made  to  exterminate 
the  gypsy  moth  or  to  hold  it  in  check  where  it  now  is,  its 
rapid  increase  and  spread  over  this  and  other  States  will 
probably  follow.  In  case  of  the  permanent  cessation  of 
public  exterminative  or  preventive  work,  the  labor  of  hold- 
ing the  gypsy  moth  in  check  or  of  repressing  its  destruc- 
tive outbreaks  will  devolve  upon  the  citizen  and  especially 
upon  the  farmer. 

In  considering  the  methods  most  useful  to  the  fanner  for 
the  destruction  of  the  gypsy  moth,  it  is  well  to  inquire,  first, 
what  class  of  farming  crops  are  most  liable  to  injury  by  the 
pest.  As  the  gypsy  moth  feeds  by  preference  on  trees,  shrubs 
and  foliaceous  plants,  those  farmers  who  devote  themselves 
entirely  to  dairying  or  grain  raising  will  be  likely  $o  suffer 
least.  Market-gardeners  have  less  to  fear  from  the  gypsy 


METHODS  FOR  THE  FARMER.      195 

moth  than  the  general  farmer  or  fruit  grower.  The  well-to- 
do  market-gardener  who  raises  little  or  no  fruit  has  few  trees 
on  his  land  to  care  for ;  his  methods  of  cultivation  are  inten- 
sive, and  he  is  obliged  to  employ  a  number  of  field  hands 
in  his  business.  He  is  therefore  better  able  to  protect  his 
crops  against  the  attacks  of  an  insect  like  the  gypsy  moth 
than  is  the  general  farmer  or  the  small  farmer  who  has  to 
depend  largely  on  his  own  labor.  There  would  be  less 
danger  to  the  interests  of  the  agriculturist  in  thickly  settled 
districts  where  market-gardening  is  carried  on  than  in  thinly 
settled  sections  where  farms  are  larger  and  less  highly  culti- 
vated, where  much  wood  is  grown  and  where  there  are  many 
orchards.  In  such  regions  the  waste  and  wooded  land,  where 
the  moth  might  breed  and  where  little  could  be  done  by  the 
owners  to  check  it,  greatly  exceed  in  area  the  cultivated 
land,  where  its  ravages  would  do  the  greatest  injury. 

In  considering,  then,  the  means  most  useful  to  the  farmer 
for  controlling  or  exterminating  the  moth,  we  must  choose 
those  most  readily  available  to  the  general  farmer  of  moder- 
ate means. 

Burning  the  eggs  or  killing  them  by  means  of  creosote  or 
other  oils  are  the  methods  which  can  be  used  most  effectually 
by  most  farmers.  The  work  can  be  done  during  the  late 
fall,  winter  and  early  spring,  —  a  time  of  the  year  when 
most  farmers  are  not  overburdened  with  the  labors  and  cares 
incidental  to  planting  and  harvesting.  If  this  is  thoroughly 
done  in  an  orchard,  there  need  be  no  fear  of  the  fruit  crop 
being  destroyed  in  the  ensuing  summer  by  the  gypsy  moth 
unless  the  orchard  is  invaded  from  without  by  caterpillars 
which  have  bred  in  the  woods  or  upon  shade  trees. 

If  shade  trees  are  near  the  orchard,  all  the  orchard  trees 
cleared  of  eggs  should  be  banded  with  insect  lime  or  supplied 
with  tree  protectors,  either  of  which  will  go  far  toward 
protecting  them  from  the  inroads  of  migrating  caterpillars. 
But  if  there  is  a  tract  of  badly  infested  woodland  near  the 
orchard,  the  bands  will  be  of  little  use  in  protecting  the 
trees  against  the  invasion  of  the  multitude  of  caterpillars. 
In  such  cases  the  most  economical  plan  would  be  to  cut 
down  all  the  infested  woods  and  burn  over  the  ground.  Few 
farmers  can  afford  to  attempt  to  keep  the  pest  out  of  wood- 


196  THE   GYPSY  MOTH. 

land,  as  the  cost  of  the  labor  would  be  more  than  the  value 
of  the  wood.  If  precautionary  measures  have  been  neg- 
lected, and  the  caterpillars  appear  in  swarms,  they  may  strip 
the  trees  before  arriving  at  an  age  when  they  will  seek  the 
burlap. 

When  small  caterpillars  are  very  numerous  upon  the  trees, 
spraying  with  arsenate  of  lead  at  the  rate  of  thirty  pounds 
to  one  hundred  and  fifty  gallons  of  water  will  destroy  most 
of  them.  If  arsenate  of  lead  is  not  at  hand,  two  or  three  good 
sprayings  with  Paris  green  in  May  will  greatly  lessen  their 
numbers.  The  trees  may  be  afterwards  burlapped,  and  the 
caterpillars  killed  as  they  gather  day  by  day  under  the  bur- 
laps. A  small  burning  tank  with  a  cyclone  burner  might  be 
used  to  stay  the  march  of  an  invading  host  of  these  cater- 
pillars, and  would  check  them  anywhere.  (See  Plate  XX.) 
The  care  of  trees  and  the  general  cleanliness  of  grounds  will 
do  much  toward  rendering  an  orchard  an  unfit  dwelling-place 
for  the  gypsy  moth,  and  will  facilitate  the  moth's  destruction. 

THE  ANNUAL  INSPECTION. 

The  inspection  and  egg-killing  in  the  infested  district  and 
the  inspection  in  the  towns  in  its  vicinity  during  the  late  fall, 
winter  and  early  spring  are  the  chief  means  of  preventing 
the  dissemination  of  the  moth,  and  the  first  and  most  impor- 
tant steps  toward  extermination.  It  is  by  examining  the 
trunks  and  the  lower  surfaces  of  large  limbs  of  trees  during 
this  search  that  most  of  the  conspicuous  .egg-clusters  are 
found.  In  this  way  most  of  the  colonies  of  the  moth  have 
been  discovered.*  It  is  for  the  prosecution  of  this  work 
that  the  most  efficient  and  experienced  men  are  retained. 
The  inspection  goes  on  through  the  winter  months,  except 
when  interrupted  by  severe  stQrms,  deep  snow  or  the  ex- 
haustion of  the  appropriation. 

Bo  long  as  there  are  moths  in  the  district  at  present  in- 
fested, just  so  long  will  there  be  danger  of  their  distribution 
throughout  that  district  and  to  adjacent  towns ;  the  danger 


*  Webster  defines  a  colony  (under  the  head  of  natural  history)  as  a  number  of 
animals  or  plants  living  together  beyond  their  usual  range.  In  the  gypsy-moth  work 
the  word  "  colony  "  has  been  applied  to  the  moth  when  it  has  been  found  isolated 
from  others  of  its  kind  by  a  belt  of  uninfested  country. 


THE   ANNUAL  INSPECTION.  197 

increasing  or  decreasing,  according  to  the  increase  or  reduc- 
tion of  the  number  of  the  moths,  especially  along  highways 
or  in  cultivated  lands  and  woodlands  most  frequented  by 
man. 

Each  autumn,  as  soon  as  the  foliage  is  well  off  the  trees, 
the  most  experienced  employees  of  the  Board  are  organized 
into  squads,  which  are  set  to  work  examining  such  territory 
within  the  infested  towns  as  has  not  been  recently  inspected. 
Many  colonies  have  thus  been  found  by  careful  search  within 
the  region  known  in  1891  to  be  infested.  Much  time  and 
money  have  been  spent  in  this  search,  but  money  enough 
has  not  been  provided  in  any  year  to  make  the  search 
thorough  and  complete.  To  provide  against  the  spread  of 
the  moth,  more  or  less  of  this  kind  of  work  has  been  done 
each  year  in  the  towns  outside  of  the  infested  region.  In 
this  outside  search  considerable  time  and  money  have  been 
expended,  and  only  a  few  small  colonies  of  the  moth  have 
been  found.  These  were  all  at  a  short  distance  outside 
the  boundary  of  the  region  known  in  1891  to  be  infested. 
Though  this  search  does  not  at  first  sight  appear  to  have 
furnished  results  proportionate  to  the  expense  incurred,  yet, 
had  the  colonies  not  been  found  and  stamped  out  of  exist- 
ence, any  one  of  them  might  have  increased  and  spread 
like  the  original  Trouvelot  colony. 

As  the  prevention  of  the  spread  of  the  moth  and  its  exter- 
mination are  the  objects  contemplated  by  the  statute  author- 
izing the  work,  this  search  of  towns  adjacent  to  the  infested 
region  must  continue  so  long  as  the  region  continues  to  be 
infested ;  otherwise,  there  can  be  no  absolute  assurance  that 
the  moths  are  not  spreading  beyond  the  limits  of  the  region 
in  which  the  work  is  carried  on. 

As  the  search  extends  farther  away  from  the  centre  of  the 
infested  region,  the  territory  to  be  examined  becomes  greater, 
increasing  the  expense,  while  the  likelihood  of  its  being  in- 
fested diminishes.  Therefore,  in  towns  next  outside  those 
immediately  adjacent  to  the  infested  region  the  search  is 
confined  to  those  places  which  experience  has  shown  are 
most  likely  to  become  infested,  mainly  the  villages  and  bor- 
ders of  highways.  Especial  attention  is  paid  to  all  points 
which  by  reason  of  the  character  of  the  business  of  the  resi- 


198  THE  GYPSY  MOTH. 

dents  appear  to  have  been  particularly  exposed  to  infesta- 
tion. 

Beyond  these  towns  only  the  borders  of  railways,  certain 
highways,  the  centres  of  villages  and  such  estates  as  are 
believed  to  have  been  exposed  to  a  possibility  of  infestation 
are  inspected.  A  few  cities  which  are  centres  of  trade  and 
travel  form  an  exception  to  this  rule.  They  have  been  more 
thoroughly  inspected.  The  following  cities  and  towns  have 
been  more  or  less  thoroughly  looked  over.  Some  have  been 
visited  only  once,  but  most  of  them  have  been  inspected 
several  times  during  the  last  five  years.  In  none  of  them 
has  any  trace  of  the  moth  been  found  :  — 

Bedford.  Ipswich.  North  Andover. 

Boxford.  Lincoln.  Quincy. 

Billerica.  Lowell.  Rowley. 

Brookline.  Middleton.  Sudbury. 

Concord.  Manchester.  Topsfield. 

Dedham.  Milton.  Tewksbury. 

Essex.  Newton.  Wilmington. 

Georgetown.  Newbury.  Wayland. 

Gloucester.  Newburyport.  Weston. 

Hamilton.  North  Reading.  Wenham. 
Hull. 

MEASURES  FOR  THE  INFORMATION  OF  THE  PUBLIC. 
The  Board  of  Agriculture  has  from  the  first  believed  that 
success  in  the  work  of  preventing  the  spread  and  securing 
the  extermination  of  the  gypsy  moth  could  not  be  hoped  for 
without  the  intelligent  co-operation  of  the  public.  Every 
effort,  consistent  with  the  letter  and  meaning  of  the  statute 
under  which  the  work  has  been  carried  on,  has  been  made 
to  diffuse  information  in  regard  to  the  identity  and  character 
of  the  pest  and  the  laws  enacted  and  regulations  made  for 
its  destruction.  The  rules  and  regulations  of  the  gypsy 
moth  committee  have  been  frequently  advertised  in  the  daily 
papers.  Every  facility  has  been  offered  to  the  daily  and 
weekly  press  in  regard  to  the  publication  of  illustrated  arti- 
cles upon  the  gypsy  moth.  Cuts  of  the  moth  have  been 
loaned  many  newspapers,  and  have  had  a  wide  circulation. 
Information  has  been  frequently  given  to  the  agricultural 
press. 


DISTRIBUTING  INFORMATION.  199 

The  prejudice  existing  against  the  spraying  and  other  feat- 
ures of  the  work,  which  was  expressed  in  the  local  press 
in  1890,  continued  to  find  some  expression  in  1891.  The 
papers,  however,  gave  the  work  of  the  Board  of  Agriculture 
a  wide  publicity.  We  can  do  no  less  than  acknowledge  the 
spirit  of  fairness  of  the  press  of  the  State,  and  the  willing- 
ness manifested  to  publish  everything  in  regard  to  the  work 
which  would  be  of  interest  to  the  people.  Yet  false  reports 
as  to  the  appearance  of  the  gypsy  moth  in  various  places  at 
a  distance  from  the  infested  region  have  been  frequently  and 
widely  circulated.  These  appear  to  originate  not  with  the 
newspapers  themselves  but  with  citizens  who,  believing  that 
they  have  discovered  the  gypsy  moth  on  their  premises,  can- 
not wait  to  notify  the  Board,  but  immediately  rush  into  print 
and  so  give  the  alarm.  In  all  such  cases  it  has  been  found 
upon  investigation  that  the  injury  noticed  was  caused  by  some 
other  insect.  Yet  these  local  ' '  scares  "  have  assisted  in  arous- 
ing the  interest  of  the  people,  and  leading  them  to  further 
investigation  of  the  appearance  and  character  of  the  moth. 

Early  in  1891  arrangements  were  made  with  an  artist  for 
drawings  of  the  gypsy  moth  to  be  reproduced  for  illustra- 
tion. A  colored  plate  (Plate  I.  of  this  report)  was  prepared 
and  printed  in  the  first  annual  report  of  the  State  Board 
of  Agriculture  on  the  extermination  of  the  gypsy  moth. 
Ten  thousand  copies  of  this  report  were  printed  and  dis- 
tributed throughout  the  Commonwealth,  especially  in  and 
near  the  infested  district.  Fifteen  hundred  extra  copies 
of  the  plate  were  also  printed,  to  be  used  in  connection 
with  other  material  and  for  posting  in  public  places,  such 
as  post-offices,  schools,  libraries  and  museums.  One  hun- 
dred and  fifty  glass-covered  cases,  containing  specimens 
of  the  different  forms  of  the  gypsy  moth,  preserved,  mounted 
and  labelled,  were  prepared  for  exhibition  in  the  infested 
district,  as  well  as  for  museums  and  other  public  places  in 
the  State.  A  bulletin  of  information  was  also  prepared,  and 
five  hundred  copies  were  printed  in  large  type  and  framed. 
In  the  centre  of  each  frame  was  placed  one  of  the  colored 
plates  representing  the  different  forms  of  the  gypsy  moth ;  a 
printed  explanation  accompanied  the  plate.  These  frames 
were  placed  in  prominent  positions  in  post-offices,  mostly 


200  THE  GYPSY  MOTH. 

in  eastern  Massachusetts.  A  large  frame  containing  in  addi- 
tion to  the  bulletin  a  photograph  of  the  moth's  ravages,  and 
having  a  specimen  case  attached,  was  placed  in  the  main  post- 
office  of  each  city  or  town  in  the  infested  district. 

In  1891  a  bulletin  of  information  in  regard  to  spraying  for 
the  gypsy  moth  and  other  insects  was  printed  in  pamphlet 
form  and  distributed  through  the  infested  district.  Some 
fifty  thousand  copies  of  the  law  of  1891,  providing  for  the 
extermination  of  the  gypsy  moth,  together  with  the  rules  and 
regulations  under  which  the  work  is  conducted,  have  been 
printed  and  distributed  among  the  people  of  the  infested 
district  and  in  towns  near  by.  The  law  and  the  rules  and 
regulations  were  also  printed  in  poster  form  and  posted  in 
many  public  places.  Many  placards  containing  certain  sec- 
tions of  the  law  were  also  printed  and  posted.  Each  season 
from  twenty  thousand  to  twenty-five  thousand  copies  of  the 
annual  report  on  the  gypsy  moth  (each  with  a  colored  plate 
of  the  insect)  have  been  printed  for  distribution,  in  addition 
to  the  nine  hundred  copies  annually  printed  for  the  use  of  the 
Legislature.  Circular  letters,  calling  the  attention  of  citizens 
to  the  threatening  danger  from  the  invasion  of  the  moth, 
have  been  printed  and  sent  with  or  without  the  reports  to 
newspapers  and  citizens  throughout  the  State.  Lectures  on 
the  gypsy  moth  and  the  means  of  its  extermination  have  been 
given  by  the  secretary  of  the  Board  of  Agriculture,  the  ento- 
mologist and  the  director.  Other  speakers  have  frequently 
spoken  on  the  same  subject  at  farmers'  institutes  and  other 
meetings. 

When  the  Massachusetts  exhibit  at  the  World's  Columbian 
Exposition  at  Chicago  was  being  prepared,  the  committee 
in  charge  requested  the  Board  of  Agriculture  to  prepare  an 
exhibit  for  the  exposition.  This  was  done,  and  the  exhibit 
occupied  a  central  place  in  the  Massachusetts  building  at  the 
fair.  It  consisted  of  a  glass  case  seven  feet  in  height,  contain- 
ing a  representation  of  an  apple  tree  denuded  of  its  leaves 
by  the  gypsy-moth  caterpillars,  and  exhibiting  on  its  trunk 
and  branches  all  forms  of  the  moth,  together  with  many  of 
the  vertebrate  and  invertebrate  enemies  of  the  moth,  includ- 
ing birds,  fowls,  predaceous  beetles  and  parasites.  Pho- 
tographs showing  the  destructiveness  of  the  moth  were 


FALSE  ALARMS.'  201 

exhibited.  A  large  amount  of  printed  matter  in  regard  to 
the  moth  was  distributed  at  the  fair. 

In  October,  1895,  in  response  to  a  request  received  from 
the  Massachusetts  Charitable  Mechanic  Association,  this  ex- 
hibit was  sent  to  the  fair  held  in  the  Mechanics  building, 
Boston,  where  it  was  exhibited  together  with  another  case 
containing  sections  of  tree  trunks  and  other  objects  on  which 
the  egg-clusters  of  the  gypsy  moth  had  been  laid.  There  was 
also  a  collection  of  bromide  enlargements  of  photographs, 
showing  the  moth  as  in  nature,  its  ravages  and  the  means  of 
destroying  it.  At  the  request  of  L.  O.  Howard,  entomolo- 
gist of  the  United  States  Department  of  Agriculture,  dupli- 
cates of  some  of  these  bromides  were  also  sent  to  the  Cotton 
States  and  International  Exposition  at  Atlanta,  Ga.,  where 
they  were  exhibited  as  a  part  of  the  entomological  exhibit  of 
the  United  States  Department  of  Agriculture. 

The  measures  taken  to  inform  the  public  have  succeeded 
in  arousing  public  interest  to  such  an  extent  that  many 
citizens  of  the  State  immediately  report  to  the  Board  any 
injurious  insects  which  appear  to  them  to  be  gypsy  moths. 
Such  reports  are  sometimes  received  from  other  States. 
Many  false  alarms  of  the  moth's  presence  have  been  sent  in, 
and  all  have  been  investigated.  Reports  of  the  appearance 
of  insects  which  were  wrongly  supposed  to  be  the  gypsy 
moth  have  been  received  from  the  following  places  :  — 

Places  from  which  False  Alarms  have  been  received. 

Massachusetts.  Brockton.  Georgetown. 

Acton.  Brookfield.  Gloucester. 

Andover.  Bourne.  Grafton. 

Ashburnham.  Chester.  Groton. 

Athol.  Concord.  Holden. 

Abington.  Charlton.  Hopedale. 

Amesbury.  Carlisle.  Haverhill. 

Auburn.  Clinton.  Holliston. 

Billerica.  Dedham.  Hyde  Park. 

Berlin.  Duxbury.  Hingham. 

Braintree.  Easton.  Hudson. 

Bedford  Fall  River.  Hull. 

Bolton.  Foxborough.  Ipswich. 

Boxford.  Fitchburg.  Lincoln. 

Brookline.  Framingham.  Lowell. 

Bridgewater.  Gill.  Lawrence. 


202 


THE   GYPSY   MOTH. 


Places  from  ivhich  False 

Alarms  have  been  rece 

ived  —  Concluded. 

Massachusetts  —  Con. 

Rehoboth. 

Connecticut. 

Maryborough. 

Scituate 

Fairfield. 

Marshfield. 

Southborough  . 

Glastonbury. 

Merrimac. 

Sterling. 

Ridgefield. 

Milford. 

Sutton. 

Methuen. 

Sudbury. 

Maine. 

Manchester. 

Springfield. 

Cape  Porpoise. 

Maynard. 

Templeton. 

Sabbatus. 

Milton. 

Tewksbury. 

Monson. 

Townsend. 

New  Hampshire. 

Newburyport. 

Tyngsborough. 

Barnstead. 

Newton. 

Uxbridge. 

Center  Harbor 

Needham. 

Wey  mouth. 

Haverhill. 

Newbury. 

Wenham. 

Kensington. 

Northbridge. 

West  Bridgewater. 

Kingston 

Norwood. 

Wilmington. 

Lakeport. 

North  Andover. 

Weston. 

Portsmouth. 

North  Brookfield. 

Westborough. 

Pratts. 

North  Reading. 

West  Newbury. 

Seabrook. 

Pittsfield. 

Wellesley. 

Pepperell. 

Wayland. 

Iowa. 

Plymouth. 

Wrentham. 

Fort  Madison. 

Princeton. 

Worcester. 

Quincy. 

Vermont. 

Randolph. 

Rhode  Island. 

Green  River. 

Rowley. 

Providence. 

Rockport. 

Pawtucket. 

In  all  cases  the  damage  reported  was  caused  by  some 
other  insect.  The  many  reports  thus  received  are  gratify- 
ing, indicating  as  they  do  a  public  interest  in  the  work, 
and  a  desire  to  aid  as  far  as  possible  in  stamping  out  the 
pest.  The  investigations  in  other  States  have  been  made 
mainly  to  prove  or  disprove  the  claim  that  the  gypsy  moth 
is  confined  in  America  to  a  limited  district  in  Massachusetts. 
This  is  the  theory  on  which  the  work  of  extermination  has 
so  far  proceeded,  and  no  proof  has  ever  been  given  that  it 
has  been  found  outside  of  this  district. 


PLATE  XXXV.     Baltimore  orioles  and  nest. 


NATURAL  ENEMIES. 


ENEMIES  OF  THE  GYPSY  MOTH. 

INSECT-EATING  BIRDS. 

Since  the  work  of  preventing  the  spreading  and  securing 
the  extermination  of  the  gypsy  moth  in  Massachusetts  was 
placed  in  the  hands  of  the  Board  of  Agriculture  in  1891, 
particular  attention  has  been  paid  to  the  natural  enemies  of 
the  moth.  All  persons  employed  in  the  work  have  been 
instructed  to  watch  for  enemies  or  parasites,  and  keep  a 
record  of  all  observations  made.  In  accordance  with  these 
instructions,  voluminous  notes  now  covering  many  hundred 
pages  have  been  made.  Many  enemies  of  the  moth  have 
been  studied  both  under  natural  conditions  and  in  confine- 
ment. Search  has  been  made  through  European  literature 
for  information  in  regard  to  the  enemies  of  the  moth  abroad. 
Much  information  bearing  upon  the  subject  has  also  been 
obtained  by  foreign  correspondence.  In  apportioning  the 
preparation  of  the  report  on  the  natural  enemies,  the  task  of 
preparing  a  report  on  the  birds  was  assigned  to  me.  My 
colleague,  Professor  Fernald,  will  treat  of  the  other  enemies 
of  the  moth. 

The   Usefulness  of  Birds  as  Insect  Destroyers. 

The  subject  of  birds  versus  insects  is  a  most  important 
one.  The  influence  of  birds  on  the  agriculture  of  a  country 
is  incalculable.  The  protection  or  destruction  of  native  birds 
and  the  introduction  of  foreign  species  are  subjects  worthy 
of  the  most  thoughtful  consideration  of  the  agricultural 
department  of  any  government. 

Land  birds  fulfil  their  part  in  many  ways  in  preserving 
the  balance  of  nature,  but  chiefly  by  doing  much  toward 
holding  in  check  the  increase  of  the  insect  world,  which,  if 
unrestricted,  would  swarm  over  and  devastate  the  earth. 

Birds  are  among  the  most  highly  organized  of  vertebrate 
animals.  In  them  we  find  the  greatest  activity  and  the 
highest  temperature  of  the  blood.  To  maintain  this  tern- 


204  THE  GYPSY  MOTH. 

perature  and  supply  the  tremendous  waste  of  the  tissues 
caused  by  this  activity  a  great  quantity  of  food  is  necessary. 
Excellent  provision  is  made  by  nature  for  the  rapid  digestion 
and  assimilation  of  a  great  amount  of  food.  In  August, 
1895,  two  young  crows  were  confined  at  the  experiment 
station  in  Maiden,  and  observations  were  made  on  their  feed- 
ing habits.  The  time  from  the  entrance  of  the  food  into  the 
mouth  to  the  first  voiding  of  excreta  containing  remains  of 
the  food  eaten  was  usually  about  one  and  one-half  hours.  It 
is  probable  that  digestion  is  still  more  rapid  in  the  smaller 
insect-eating  birds.*  The  common  titmouse  or  chickadee 
(Pai*us  atricapiUus)  is  one  of  the  smaller  birds  of  New  Eng- 
land, yet  the  good  accomplished  by  it  in  destroying  the  eggs 
of  insects  injurious  to  orchard  and  forest  trees  is  almost 
beyond  belief.  I  have  given  elsewhere  an  estimate,  based 
on  careful  observations  and  dissections,  that  in  twenty-five 
days  one  of  these  birds  will  destroy  138,750  eggs  of  the 
canker-worm  moth  (Anisopteryx pometaria)  .f 

Prof.  Samuel  Aughey,  who  fed  confined  plovers  on  in- 
sects, found  that  they  would  eat  on  an  average  202  locusts 
and  other  large  insects  per  day.J 

Professor  Treadwell  fed  to  a  young  robin  in  twelve  hours 
forty-one  per  cent,  more  than  its  own  weight  in  worms.  The 
same  bird  consumed  nearly  half  its  own  weight  of  beef  in  a 
day.§ 

At  this  rate  a  man  would  eat  daily  about  seventy  pounds 
of  meat.  Because  of  their  enormous  appetites,  birds  are 
most  potent  factors  for  good  or  ill.  It  is  well  known  that 
crows  and  blackbirds  destroy  vast  quantities  of  grain  for  a 
short  season  when  they  swarm  upon  the  fields ;  but  their 
services  in  destroying  injurious  insects  are  not  generally 
recognized. 

*  According  to  Maynard  the  indigestible  remains  of  food  are  excreted  by  the  cedar- 
bird  in  one-half  hour  after  eating.  (See  "  Birds  of  Eastern  North  America,"  C.  J. 
Maynard.) 

t  Bulletin  on  "  Birds  as  protectors  of  orchards,"  Massachusetts  Crop  Report, 
July,  1895,  published  by  the  Massachusetts  State  Board  of  Agriculture. 

%  First  report  United  States  Entomological  Commission,  1877,  page  343. 

§  "  Birds  of  New  England,"  by  E.  A.  Samuels,  page  159.  The  paper  on  this 
subject  was  originally  read  by  Professor  Treadwell  before  the  Boston  Society  of 
Natural  History. 


USEFULNESS   OF  BIKDS.  205 

The  activity  of  birds,  as  shown  in  running,  climbing  trees, 
hopping  or  flying,  together  with  their  powers  of  vision, 
renders  them  particularly  adapted  for  searching  out,  over- 
taking and  destroying  insects.  Birds  often  assemble  where 
insect  outbreaks  occur,  and  assist  in  checking  great  insect 
invasions. 

In  a  search  through  agricultural,  entomological  and  orni- 
thological literature,  we  find  many  instances  on  record  in 
both  hemispheres  where  birds  have  been  instrumental  in 
saving  crops  or  forests  by  destroying  injurious  insects. 
Samuels  states  that  in  1847,  as  an  immense  forest  in  Pom- 
erania  was  on  the  brink  of  being  utterly  ruined  by  caterpil- 
lars, it  was  suddenly  and  very  unexpectedly  saved  by  a  flock 
of  cuckoos,  who  established  themselves  in  the  place  for  a 
few  weeks  and  thoroughly  cleaned  each  tree.* 

During  the  great  locust  invasions  in  the  West  the  investi- 
gations of  Professor  Aughey,  as  published  in  the  first  report 
of  the  United  States  Entomological  Commission,  showed 
that  birds  were  among  the  greatest  enemies  of  locusts,  and 
that  in  many  instances  when  the  farmers  had  given  up  the 
battle  against  the  "grasshoppers,"  the  crops  were  saved  by 
the  flocks  of  birds  that  descended  upon  the  fields,  destroying 
immense  numbers  of  the  feeding  locusts,  f 

Many  instances  are  on  record  where  a  great  increase  of 
insect  pests  has  followed  the  destruction  of  birds.  George 
Kearly,  in  the  "Entomologist's  Weekly  Intelligencer," 
speaks  of  an  outbreak  of  insect  pests  in  a  park  at  Brussels, 
in  which  the  gypsy  moth  was  one  of  the  chief  offenders,  hav- 
ing stripped  well-nigh  all  the  trees  of  their  foliage.  He  says 
this  great  increase  of  insects  followed  soon  after  and  was 
caused  by  the  destruction  of  sparrows  and  other  birds  in  the 
park,  by  order  of  the  authorities.^  In  a  letter  recently 
received  from  J.  O.  Clercy,  secretary  of  the  Society  of 
Natural  Sciences,  Ekaterinburg,  Russia,  he  states  that  the 
ravages  of  two  species  of  cutworms  and  some  ten  species 


*  E.  A.  Samuels,  In  report  of  Massachusetts  State  Board  of  Agriculture,  1865-66, 
page  117. 

t  Report  of  the  United  States  Entomological  Commission,  1877,  page  338. 
I  The  "Entomologist's  Weekly  Intelligencer,"  1858,  Vol.  4,  page  192. 


206  THE  GYPSY  MOTH. 

of  locusts  contributed,  together  with  the  want  of  rain,  to 
starve  the  inhabitants  in  that  region  in  1891  and  1892. 
One  of  the  causes,  he  says,  which  permitted  such  a  numer- 
ous propagation  of  insect  pests  was  the  almost  complete  de- 
struction of  birds,  most  of  them  having  been  killed  and 
sent  abroad  by  wagon  loads  for  ladies'  hats.  A  law  for  the 
protection  of  birds  has  now  been  enacted,  and,  says  Clercy, 
"the  poor  little  creatures  are  doing  their  best  to  reoccupy 
their  old  places  in  our  woods  and  gardens.  This  reoccu- 
pation,  however,  does  not  go  on  as  rapidly  as  did  their 
destruction." 

Many  species  of  water  birds,  the  gulls  and  terns  especially, 
are  useful  as  insect  destroyers.  In  1848  the  crops  of  the 
Mormons  in  Utah  were  attacked  by  the  Western  cricket (Ana- 
brus  simplex),  which  came  down  in  great  armies  from  the 
highlands  about  Salt  Lake.  These  crickets  had  already 
destroyed  a  considerable  portion  of  the  crops,  when  great 
flocks  of  gulls  appeared  and  ate  the  crickets.  Hon.  George 
Q.  Cannon  says:  "Black  crickets  came  down  by  millions 
and  destroyed  our  grain  crops ;  promising  fields  of  wheat 
in  the  morning  were  by  evening  as  smooth  as  a  man's  hand, 
—  devoured  by  the  crickets.  Sea  gulls  came  by  hundreds 
and  thousands,  and,  before  the  crops  were  entirely  destroyed, 
these  gulls  devoured  the  insects  so  that  our  fields  were 
entirely  freed  from  them."  * 

This  occurrence  is  well  authenticated  and  testified  to  by 
many  eye- witnesses. f 

While  some  ornithologists  regard  birds  as  by  far  the  most 
important  natural  enemies  of  injurious  insects,  many  ento- 
mologists believe  that  insect  and  vegetable  parasites  are  more 
useful  in  this  respect  than  birds;  yet  some  of  the  most 
eminent  economic  entomologists,  who  have  had  occasion  to 
observe  the  insect-eating  habits  of  birds  in  connection  with 
great  outbreaks  of  insect  pests,  have  been  among  the  first  to 


»  "  Insect  Life,"  Vol.  7,  No.  3,  page  275. 

t  See  the  nineteenth  annual  report  of  the  secretary  of  the  Massachusetts  Board 
of  Agriculture,  1871,  page  76 ;  the  report  of  the  United  States  Commissioner  of  Ag- 
riculture, 1871,  page  79;  also  the  second  report  of  the  United  States  Entomological 
Commission  for  1878  and  1879,  relating  to  the  Rocky  Mountain  locust,  page  166, 
A.  S.  Packard,  Jr. 


MOTH-EATING   BIRDS.  207 

give  public  expression  to  their  appreciation  of  the  value  of 
birds  as  destroyers  of  noxious  insects.* 

A  study  of  the  food  of  insect-eating  birds  leads  to  the  belief 
that  if  in  any  way  their  numbers  and  efficiency  can  be  aug- 
mented, an  increase  in  agricultural  products  will  be  secured. 

BIRDS    SEEN   TO   FEED   UPON   THE    GYPSY   MOTH. 

Thirty-eight  species  of  birds  have  been  identified  when 
feeding  upon  the  gypsy  moth  in  one  or  more  of  its  forms. 
They  are  as  follows  :  — 

Yellow-billed  cuckoo,   .        .        .  Coccyzus  americanus.     (Linn.) 

Black-billed  cuckoo,      .        .        .  Coccyzus  erythrophlhalmus.    (Wils.) 

Hairy  woodpecker,        .        .        .  Dryobates  villosus.     (Linn.) 

Downy  woodpecker,      .        .        .  Dryobates  pubescens.     (Linn.) 

Pigeon  woodpecker,      .        .        .  Colaptes  auratus.     (Linn.) 

King  bird,      .        .        .        .        .  Tyrannus  tyrannus.     (Linn.) 

Great-crested  flycatcher,       .        .  Myiarchus  crinitus.     (Linn.) 

Phoebe, Sayornis  phcebe.     (Lath ) 

Wood  pewee Contopus  virens.     (Linn.) 

Least  flycatcher Empidonax  minimus.    Baird. 

Blue  jay,        .        .        ...        .  Cyanocilta  cristata.     (Linn.) 

Crow,     .        .        .        .        .        .  Corvus  americanus.    Aud. 

Baltimore  oriole Icterus  galbula.     (Linn.) 

Purple  grackle  or  crow  blackbird,  Quiscalus  quiscula.     (Linn.) 

Chipping  sparrow,        .        .        .  Spizella  socialis.     (Wils.) 

Chewink,       .....  Pipilo  erythrophthalmus.     (Linn.) 

Rose-breasted  grosbeak,       .         .  Habia  ludoviciana.     (Linn ) 

Indigo  bird,  .....  Passerina  cyanea.     (Linn.) 

Scarlet  tanager,     ....  Piranga  erythromelas.    Vieill. 

Red-eyed  vireo,     ....  Vireo  olivaceus.     (Linn.) 

*  Townend  Glover,  first  entomologist  of  the  United  States  Department  of  Agri- 
culture, wrote  in  1871 :  "  Insectivorous  birds  are  the  best  allies  of  the  farmer,  and 
were  they  all  destroyed  there  is  little  doubt  that  it  would  be  almost  impossible  to 
raise  certain  crops."  (Report  of  the  United  States  Commissioner  of  Agriculture, 
1871,  page  71.) 

He  also  wrote :  "  A  knowledge  of  their  nature  and  habits  is  of  as  much  impor- 
tance to  the  farmer  and  fruit  culturist  as  is  the  science  of  entomology."  (Report  of 
the  United  States  Commissioner  of  Agriculture,  1865,  page  36.) 

Prof.  C.  V.  Riley,  late  entomologist  of  the  Department  of  Agriculture,  has  testified 
to  the  utility  of  birds  as  follows :  "  Few  injurious  insects  can  be  well  and  fully 
considered  without  reference  to  their  liability  to  be  devoured  by  various  natural 
enemies,  and  especially  birds."  (Report  of  the  United  States  Commissioner  of 
Agriculture,  1885,  page  210.) 

Prof.  John  B.  Smith,  State  entomologist  of  New  Jersey,  in  an  address  to  the 
farmers  of  New  Jersey,  said:  "Take  care  of  your  natural  friends!  Among  these 
the  birds  rank  highest."  ("Insecticides,  and  how  to  apply  them,"  seventeenth 
annual  report  of  the  New  Jersey  State  Board  of  Agriculture,  1889-90,  pages  294, 295.) 


208  THE   GYPSY  MOTH. 

Yellow-throated  vireo,  .        .         .  Vireo  flavifrons.    Vieill. 
White-eyed  vireo,         .        .        .  Vireo  noveboracensis.     (Gmel.) 
Black-and-white  warbler,      .         .  Mniotilta  varia.     (Linn.) 
Yellow  warbler,    ....  Dendroica  cestiva.     (Gmel.) 
Chestnut-sided  warbler,        .         .  Dendroica  pensylvanica.     (Linn.) 
Black-throated  green  warbler,     .  Dendroica  virens.     (Gmel.) 
Oven  bird,     .....  Seiurus  aurocapillus.     (Linn.) 
Maryland    yellow-throated   war- 
bler,      Geothlypis  Irichas.     (Linn.) 

American  redstart,         .        .        .  Setophaga  ruticilla.     (Linn.) 

Catbird,          .....  Oaleoscoptes  carolinensis.     (Linn.) 

Brown  thrasher,     ....  Harporhynchus  rufus.     (Linn.) 

House  wren,  .....  Troglodytes  cedon.    Vieill. 

White-breasted  nuthatch,      .        .  S-Ma  carolinensis.    Lath. 

Chickadee,     .....  Parus  atricapillus.    Linn. 

Wood  thrush,         ....  Turdus  mustelinus.     Gmel. 

American  robin,    ....  Merula  migratoria.     (Linn.) 

Bluebird, Sialia  sialis.     (Linn.) 

English  sparrow,  ....  Passer  domesticus.     (Linn.) 

Birds  which  feed  on  the  Larvce,  Pupce  and  Imagoes. 

It  is  generally  believed  by  entomologists  (judging  from 
their  writings)  that  hairy  caterpillars  have  a  certain  immu- 
nity from  the  attacks  of  birds.  In  Europe  this  appears  to 
be  true  to  some  extent  of  the  larvae  of  the  gypsy  moth.  A 
writer  in  the  "  Annales  de  PInstitut  Horticole  de  Fromont" 
says  that  in  twenty  years  of  observation  he  has  not  seen  a 
bird  bring  one  of  the  caterpillars  to  its  young.* 

Keppen,  writing  of  the  gypsy  moth  in  Kussia,  says  that 
the  cuckoo  is  the  only  bird  which  takes  them.  Grimm 
noticed  about  Saratov  that  birds  had  completely  forsaken  the 
places  where  the  caterpillars  were  usually  numerous.  This 
is  said  to  have  taken  place  also  in  the  district  of  Kirsanov  in 
the  province  of  Tambov,  f  Grimm  thinks  this  is  owing  to 

*  "  Annales  de  1'Institut  Horticole  de  Fromont,"  Vol.  5,  page  311,  Paris,  1833. 

t  This  does  not  agree  with  the  experience  of  the  forest  authorities  in  Bavaria 
during  the  recent  invasion  occasioned  by  the  spruce  moth  or  "nun"  (Liparis 
monaeha),  1889-91.  This  insect  is  closely  allied  to  the  gypsy  moth  and  was 
formerly  placed  in  the  same  genus.  The  caterpillars  are  provided  with  hairs  sim- 
ilar to  those  of  the  gypsy  caterpillars.  The  flight  of  starlings  collected  in  one 
locality  alone  was  credibly  estimated  at  10,000,  all  busy  feeding  on  the  caterpillars, 
chrysalides  and  moths,  not  to  mention  enormous  nights  of  titmice  and  finches  sim- 
ilarly engaged.  The  attraction  of  starlings  to  such  centres  became  so  great  that 
market-gardeners  felt  their  absence  seriously  in  distant  parts  of  the  country. 

"  Protection  of  "Woodlands,"  by  Hermann  Furst,  English  edition;  translated  by 
John  Nisbet,  1893,  page  126. 


OBSERVATIONS  ON  BIRDS,  209 

the  fact  that  the  body  of  the  caterpillar  is  covered  with  small 
hairs,  which  become  detached,  and,  piercing  somewhat  the 
skin  of  persons  and  animals,  cause  great  itching.* 

I  have  found  very  little  evidence  in  the  writings  of  Euro- 
pean authors  that  birds  other  than  the  cuckoo  and  the  tit- 
mice destroy  the  larvae  of  the  gypsy  moth,  although  several 
species  are  said  to  destroy  the  eggs.f  In  this  country,  how- 
ever, the  reverse  appears  to  be  true.  Few  birds  seem  to 
eat  the  eggs,  while  many  attack  all  other  forms  of  the  moth. 
In  the  season  of  1891  my  attention  was  first  called  to  the  fact 
that  certain  birds  were  devouring  large  numbers  of  the  larvae. 
The  accuracy  of  the  reports  received  was  soon  verified  by 
my  own  observations.  Several  species  of  birds  were  seen 
busily  engaged  in  eating  the  insects  wherever  they  were 
numerous.  The  inspectors  were  directed  to  record  all 
observations  made  on  birds  which  were  feeding  on  the  cater- 
pillars. 

Unfortunately,  there  were  at  that  time  only  eleven  observ- 
ers on  the  force  who  could  accurately  identify  birds  in  the 
field.  These  men  were  also  perfectly  familiar  with  the  dif- 
ferent forms  of  the  moth.  The  notes  made  by  them  indi- 
cated that  thirteen  species  of  birds  were  feeding  on  the 
moth  in  one  or  more  of  its  forms.  The  observations  begun 
in  1891  have  been  continued  during  a  part  of  each  succeed- 
ing summer.  Although  as  a  rule  they  have  been  made  inci- 
dentally in  connection  with  the  work  in  the  field,  one  or 
more  men  have  been  detailed  at  times  to  disprove  or  confirm 
reports  that  have  been  made,  or  to  watch  some  particular 
species  of  bird,  so  that  some  points  in  regard  to  its  value  as 
a  moth  destroyer  might  be  settled.  Where  the  caterpillars 
are  very  numerous,  they  cluster  in  masses  on  trees.  Cer- 
tain birds  habitually  visit  these  swarms  either  to  eat  the 
caterpillars  or  to  take  them  as  food  to  their  young.  If  the 
observer  remained  quietly  at  his  post,  he  was  able  to  view 
them  at  a  distance  of  a  few  feet  or  yards.  Each  observer  was 


*  Translated  from  "  Injurious  Insects  "  by  Theodore  Keppen,  3d  Vol.,  special 
part. 

t  In  a  recent  letter  Dr.  Ebermayer  of  Munich  names  starlings,  crows,  titmice  and 
tree  creepers  among  the  enemies  of  the  gypsy  moth  but  does  not  say  what  form  of 
the  moth  they  destroy. 


210  THE   GYPSY  MOTH. 

supplied  with  an  opera  glass,  by  means  of  which  he  could 
determine  at  a  greater  distance  whether  or  not  the  birds  were 
feeding  on  the  caterpillars  of  the  gypsy  moth.  Few  birds 
were  shot  and  few  dissections  made  as  compared  with  the 
number  of  birds  reported  as  feeding  on  the  caterpillars. 
This  might  serve  to  discredit  the  accuracy  of  the  observa- 
tions, were  they  not  made  at  close  range,  and  when  the 
caterpillars  were  large  enough  to  be  readily  identified.  No 
birds  were  shot  except  where  it  was  absolutely  necessary  to 
determine  whether  it  was  the  gypsy  moth  caterpillar  or 
some  other  upon  which  they  were  feeding.  No  observations 
were  accepted  as  conclusive  unless  the  observer  was  known 
to  be  careful  in  his  work  and  conservative  in  his  statements, 
or  unless  ample  corroborative  evidence  was  obtained.  While 
there  is  some  possibility  of  error  in  field  observations,  there 
is  also  a  possibility  of  error  in  stomach  examinations.  Di- 
gestion in  birds  is  so  rapid  that  it  is  impossible  to  specifi- 
cally identify  some  portions  of  their  insect  food  unless  the 
bird  is  killed  within  a  very  few  minutes  after  the  insects  are 
eaten.  When  birds  are  feeding  on  larvce,  a  large  proportion 
of  the  stomach  contents  is  often  unrecognizable.* 

Birds  do  not  always  swallow  hairy  caterpillars  whole.  In 
many  cases  they  tear  them  open,  eating  only  some  of  the 
internal  parts  which  are  unrecognizable  upon  dissection  of 
the  stomach.  Other  birds  appear  to  kill  wantonly  many 
caterpillars  and  moths.  Woodpeckers,  jays  and  chickadees 
have  been  seen  to  snap  them  up  and  then  drop  them  to  the 
ground,  sometimes  uninjured  but  often  mortally  hurt. 
Sparrows  and  other  birds  have  been  seen  to  kill  many  moths 
which  they  do  not  eat. 

The  Most  Useful  Birds. 

The  records  of  the  observations  made  on  birds  comprise 
one  hundred  and  fifty  typewritten  pages.  A  glance  over 
these  pages  shows  that  the  greater  number  of  observations 
have  been  made  on  less  than  a  dozen  species,  and  indicates 
that  these  are  probably  the  birds  most  useful  in  destroying 

*  Considering  the  possibility  of  error  "in  records  made  from  either  observation  or 
dissection,  it  would  seem  that  one  should  be  used  as  a  supplement  to  and  a  check 
on  the  other. 


MOST  USEFUL  BIRDS.  211 

the  gypsy  moth.  It  cannot  be  stated  with  certainty  which 
species  is  of  most  value  in  this  respect,  as  the  birds  ob- 
served vary  both  in  numbers  and  usefulness  with  the  locality 
and  season.  From  observations  made  eleven  species  are 
known  to  be  very  useful.  In  the  apparent  order  of  their  use- 
fulness they  are  :  yellow-billed  cuckoo,  black-billed  cuckoo, 
Baltimore  oriole,  catbird,  chickadee,  blue  jay,  chipping  spar- 
row, robin,  red-eyed  vireo,  yellow-throated  vireo  and  crow. 


FIG.  29.    Yellow-billed  cuckoo. 

The  cuckoo  is  the  only  bird  that  I  have  found  mentioned 
in  European  literature  as  feeding  commonly  on  the  larvae 
of  the  gypsy  moth.  Altum  says  the  cuckoo  is  efficient 
especially  in  local  ravages  of  the  moth.*  Appearances  in- 
dicate that  the  cuckoos  lead  the  rest  of  the  American  birds 
in  destroying  the  gypsy  moth.  Yet  it  must  be  considered 
that  as  these  cuckoos  are  comparatively  large  birds,  seeking 
by  preference  the  larger  larvae,  their  feeding  is  readily  ob- 
served. As  the  larvae  are  usually  swallowed  whole  by  the 
cuckoo,  their  remains  are  readily  recognized  in  the  dissected 
stomach.  It  is  difficult  to  identify  with  certainty  the  smaller 
larvae  when  they  are  eaten  by  small  birds.  If  these  small 
birds  consume  the  smaller  larvae  in  numbers  equal  to  those 
of  the  larger  ones  eaten  by  the  cuckoo,  they  are  more  benefi- 
cial, as  the  destruction  of  the  larvae  when  young  will  prevent 
the  injury  they  might  do  to  vegetation  before  the  cuckoo 
would  be  likely  to  attack  them. 

*  "  Forstzoologie,"  Vol.  III.,  page  96. 


212  THE   GYPSY  MOTH. 

Yellow-billed  Cuckoo.  —  In  1891  yellow-billed  cuckoos 
were  observed  in  several  of  the  worst  infested  localities, 
where  they  remained  nearly  all  day,  feeding  on  the  gypsy 
larvae  or  carrying  them  from  time  to  time  to  their  young. 
This  habit  of  feeding  on  hairy  larvae  seems  to  be  quite  con- 
stant with  the  cuckoos.  They  seem  to  prefer  the  gypsy 
larvae  even  to  the  pupae. 

Mr.  F.  H.  Mosher,  an  inspector  in  the  employ  of  the 
Board,  who  observed  this  species  in  1895,  says  that  it  will 
go  to  a  bunch  of  pupae  and  search  for  larvae,  pulling  out  the 
molts  or  casts,  and  will  take  pupae  only  when  larvae  are  not 
to  be  found.  This  was  noticed  in  different  individuals  of 
this  species  and  in  different  localities.  Some  of  the  cuckoos 
would  take  no  pupae  at  all,  but  would  continue  their  search 
for  larvae  until  they  found  them. 

That  the  yellow-billed  cuckoos  feed  their  young  quite  con- 
stantly on  these  larvae  is  evident  from  the  observations  made. 
The  stomach  of  one  young  cuckoo  when  examined  contained 
a  number  of  partly  digested  larvae  and  the  heads  of  sixteen 
others.  Ninety  per  cent,  of  the  stomach  contents  consisted 
of  these  larval  remains.  When  the  young  birds  were  able  to 
fly,  the  parents  would  lead  them  to  the  worst  infested  spots 
and  feed  them  frequently  with  caterpillars. 

Mr.  C.  E.  Bailey,  an  agent  of  the  Board  and  a  field  orni- 
thologist of  much  experience,  says  that  the  yellow-billed 
cuckoo  is  very  fond  of  the  gypsy  larvae,  sometimes  eating 
nine  or  ten  full-grown  ones  in  less  than  a  half  hour.  He 
also  states  that  he  has  observed  that  it  eats  more  caterpillars 
than  the  black-billed  cuckoo. 

Black-billed  Cuckoo. — The  black-billed  cuckoo  is  probably 
nearly  if  not  quite  as  useful  as  its  congener  in  destroying 
hairy  caterpillars,  and  appears  to  be  almost  equally  destruc- 
tive to  the  gypsy  moth  larvae.  From  personal  observation, 
as  well  as  from  reports  of  the  observations  of  others,  I  am 
led  to  believe  that  this  bird  does  not  feed  as  rapidly  as  the 
yellow-billed  cuckoo,  and  spends  more  time  in  beating  the 
caterpillars,  perhaps  for  the  purpose  of  killing  them,  or  pos- 
sibly to  divest  them  of  their  hairs  before  eating  them.  In 
the  end,  however,  the  caterpillar  is  swallowed  whole.  Like 
the  yellow-billed  cuckoo,  this  species  feeds  the  caterpillars 
to  its  young. 


MOST  USEFUL  BIRDS.  213 

Neither  species  of  the  cuckoo  is  very  numerous  in  the 
infested  region,  but  both  are  fairly  common  and  both  are 
attracted  by  the  gypsy  moth  to  badly  infested  orchards  or  to 
the  edges  of  badly  infested  woodland.  Five  cuckoos  have 
been  seen  at  a  time  in  an  infested  tree.  In  some  infested 
places  they  may  be  found  at  times  in  considerable  numbers, 
and  the  number  of  larvae  they  destroy  is  astonishing.  They 
frequently  take  larvae  from  under  the  burlaps. 

Baltimore  Oriole.  — The  oriole,  like  the  cuckoo,  is  a  well- 
known  destroyer  of  the  tent  caterpillar  (  Glisiocampa  Ameri- 
cana} and  other  hairy  larvae.  Several  observers  have  seen 
this  bird  taking  gypsy  larvae  from  the  burlaps.  In  1894  in 
an  orchard  in  Winchester  four  orioles  were  seen  to  follow 
along  the  rows  of  trees,  flitting  from  burlap  to  burlap,  and 
taking  the  larvae  from  under  the  cloth.  The  birds  would 
hang  to  the  burlap  while  turning  up  the  edges  and  running 
their  bills  beneath.  The  young  orioles  frequently  enjoy  a 
gypsy  moth  diet,  and  the  adult  birds  have  been  seen  day 
after  day  feeding  their  young  with  these  insects. 

Only  three  orioles'  stomachs  have  been  dissected.  One 
contained  four  nearly  full-grown  gypsy  moth  larvae,  another 
two,  and  one  was  empty.  These  dissections  probably  did 
not  fairly  indicate  the  value  of  these  birds  as  caterpillar  de- 
stroyers, as  the  orioles  have  been  seen  to  kill  caterpillars  of 
which  they  ate  only  a  small  portion. 

Catbird.  —  Where   the   gypsy  moth   has  penetrated  into 
thickets,  the  catbird  feeds  on 
the  larvae,  and,  as  the  season 
advances,  destroys  many  of 
the  pupae,  taking  both  these 
forms    of   the    moth    to    its 
young.     That   this   habit   is 
quite  constant  is  evident,  as 
the  catbird  was  seen  feeding 
on  the  larvae   in    1891,    and 
almost  daily  through  a  con- 
siderable portion  of  the  sum- 
mer of  1895  by  observers  in  several  different  towns.     The 
catbird  has  been  seen  to  take  larvae  of  all  sizes  to  its  young. 
It  is  one  of  the  birds  that  frequent  badly  infested  localities. 


214 


THE   GYPSY  MOTH. 


FIG.  31.    Chickadee. 


Chickadee.  —  The  chickadee,  though  a  small  bird,  feeds 
quite  constantly  on  the  gypsy  moth  larvae,  "skinning"  or 
tearing  to  pieces  the  larger  larvae 
which  it  cannot  swallow.  On  cap- 
turing a  large  specimen  the  bird 
usually  stands  on  the  caterpillar, 
striking  it  with  its  bill  until  the 
skin  is  torn  open,  when  it  pro- 
ceeds to  eat  the  vital  parts. 
Sometimes  the  chickadee  eats 
nearly  all  of  a  large  larva.  This 
bird  is  also  fond  of  the  pupae, 
usually  breaking  them  open  and 
eating  a  small  portion  of  the 
body  tissues  and  juices.  Chick- 
adees have  been  seen  to  feed  on 
the  female  moths. 
Blue  Jay.  —  In  infested  woodlands  or  in  orchards  near  its 
favorite  haunts  the  blue  jay  is  most  useful  as  a  caterpillar 
hunter.  Mr.  M.  J.  Flood,  formerly  in  the  employ  of  the 
Board,  who  was  stationed  in  1891  at  a  badly  infested  locality 
in  Arlington,  where  he  watched  the  gypsy  moth  larvae  for 
forty-eight  hours,  reported  that  he  saw  hundreds  of  the 
larvae  picked  up  by  this  bird.  During  the  day  he  saw  six- 
teen blue  jays  eating  the  larvae  and  pupae,  which  he  could 
see  very  distinctly  as  the  birds  held  them  in  their  bills. 
These  birds  are  known  to  be  regular  visitors  to  badly  in- 
fested trees,  yet  they  are  so  wary  that  it  is  difficult  to  observe 
them  closely.  The  prying  nature  of  the  blue  jay  stands  it 
in  good  stead  in  searching  out  hidden  larvae.  It  pecks 
them  from  the  crevices  of  the  bark  or  from  under  the  bark 
on  dead  limbs,  and  searches  every  hole.  It  frequently  visits 
burlaps  on  infested  trees,  thrusting  its  bill  under  the  burlap 
and  raising  it  enough  to  draw  out  the  hidden  larvae  beneath. 
Mr.  Mosher  reports  having  seen  the  blue  jays  feeding  larvae 
and  pupae  to  their  young.  The  jays  have  been  frequently 
seen  carrying  the  larvae  in  their  beaks,  probably  with  the 
intention  of  feeding  them  to  their  young.  Sometimes  the}^ 
pinch  or  hammer  the  larvae,  killing  them  in  wanton  sport  or 


MOST  USEFUL  BIRDS. 


215 


maiming  them  and  dropping  them  upon  the  ground.  This 
habit  of  killing  and  dropping  larvae  has  been  observed  else- 
where.* 


FIG.  32     Blue  jay. 

« 

Chipping  Sparroio.  —  Though  the  chipping  sparrow  does 
not  rank  high  among  insectivorous  birds,  and  feeds  largely 
upon  seeds  during  certain  seasons  of  the  year,  it  nevertheless 
destroys  very  many  in- 
sects, especially  lepi- 
dopterous  larvae,  which 
are  injurious  to  trees 
,and  garden  plants.  It 
is  often  seen  chasing 
flying  gypsy  moths.  It 
appears  to  be  fond  of 
gypsy  moth  caterpillars, 
and  I  have  frequently 
observed  it  in  badly 
infested  spots  catching 


^Cs 

FIG.  33.    Chipping  sparrow. 


and  killing  large  larvae.  A  young  chipping  sparrow  shot 
and  dissected  contained  a  nearly  full-grown  larva  of  the 
gypsy  moth,  which  had  been  swallowed  head  first. 

In  1891  Mr.  E.  P.  Felt  confined  (for  experimental  pur- 


*  Dr.  C.  M.  Weed  in  the  Ninth  Annual  Report  of  the  Ohio  Agricultural  Experi- 
ment Station,  1890,  p.  Iv. 


216 


THE  GYPSY  MOTH. 


poses)  a  number  of  gypsy  moth  caterpillars  in  nets  on  the 
branches  of  apple  trees.  It  was  found  almost  impossible  to 
complete  the  experiments,  as  many  of  the  caterpillars  dis- 
appeared from  the  nets.  An  examination  of  the  nets  showed 
that  they  had  been  broken  open  in  some  unknown  way.  I 
watched  one  of  the  nets  and  saw  a  chipping  sparrow  break 
through  the  netting  and  secure  one  of  the  larger  larvae.  As 
these  birds  were  frequently  seen  about  the  nets,  it  is  probable 
that  they  were  responsible  for  the  abduction  of  many  larvae 
which  disappeared.  Mr.  Felt  says  in  his  notes  that  sixty 
per  cent,  of  the  larvae  used  in  the  experiments  were  taken 
by  birds  which  broke  into  the  nets.  There  were  very  few 
of  these  larvae  in  the  vicinity,  except  those  confined  in  the 
nets. 

Robin.  —  The  robin  has  been  reported  by  several  observers 
as  feeding  upon  the  larvae  of  the  gypsy  moth,  and  by  one  as 
feeding  upon  the  pupae.  One  observer  believes  the  robin  to 
be  the  most  useful  bird  of  all ;  but  the  notes  on  this  bird  are 
lacking  in  detail.  I  can  say  nothing  from  personal  observa- 
tion in  regard  to  its  habits  of  feeding  on  the  gypsy  moth, 
except  that  it  has  been  often  seen  feeding  on  the  ground 
about  apple  trees  frequented  by  the  gypsy  moth,  or  upon  the 
lower  branches  of  such  trees,  also  in  trees  in  badly  infested 
woodland. 

Red-eyed  Vireo.  — This  bird  has  been  seen  by  many  observ- 
ers to  feed  on  the  gypsy  moth  larvae.  It  probably  feeds  its 
young  quite  regularly  on  the  larvae.  The  vireos  are  known 

to  be  caterpillar  hunters,  but 
are  believed  to  prefer  smooth- 
skinned  species.  They,  how- 
ever, frequently  break  open 
the  nests  of  the  tent  cater- 
pillar to  get  at  the  hairy 
larvae  within.  This  bird  usu- 
ally places  the  gypsy  moth 
larva  on  a  limb,  and  pulling 
it  to  pieces  eats  the  pieces 
separately ;  yet  it  has  been 

F».84.    Red-eyed  Vireo.  geen     often     to    eftt    th 

whole  and  also  to  feed  it  alive  to  the  young  birds. 


MOST  USEFUL  BIRDS.  217 

Yellow-throated  Vireo. — Mr.  C.  E.  Wood,  an  inspector 
in  the  employ  of  the  Board,  writes  that  he  saw  a  yellow- 
throated  vireo  take  a  large  larva,  alight  on  a  limb  with  it, 
and,  placing  one  foot  on  it,  peck  its  head  off  and  give  the 
body  to  a  young  full-fledged  bird  which  was  waiting  to  be 
fed.  The  young  bird  took  the  body  of  the  larva,  placed  it 
on  the  limb  under  one  foot,  and,  pecking  off  a  few  small 
pieces  swallowed  the  rest  whole.  The  yellow-throated  vireo 
has  been  seen  by  several  observers  to  catch  and  eat  the 
larvae,  and  is  probably  nearly  as  useful  in  this  respect  as 
the  red-eyed  vireo. 

Grow.  — The  crows  in  the  infested  region  are  so  shy  that 
it  is  difficult  to  get  near  enough  to  them  to  observe  care- 
fully their  feeding  habits.  It  was  not  until  1895  that  they 
were  actually  seen  to  feed  upon  the  gypsy  moth,  though  it 
had  been  noted  that  they  sometimes  frequented  badly  infested 
places.  They  had  also  been  seen  to  take  their  young  to  in- 
fested localities,  where  they  were  apparently  feeding  them 
with  the  larvae  or  pupae.  In  the  summer  of  1895  the  prob- 
ability of  their  feeding  upon  the  gypsy  moth  was  made  a 
certainty  by  the  observations  of  Mr.  Mosher,  whose  work 
in  observing  birds  has  been  done  with  the  most  painstaking 
and  patient  care. 

The  prying,  inquisitive  habits  of  the  family  are  well  illus- 
trated by  the  crow  when  searching  for  gypsy  moth  larvae  and 
pupae.  Dead  bark  is  torn  off  from  branches,  clumps  of 
bushes  are  penetrated,  and  rubbish  on  the  ground  is  over- 
hauled by  the  bird  in  its  search  for  the  insects.  Mr.  Mosher 
watched  a  crow  which  alighted  within  thirty  feet  of  him  on 
a  branch  above  his  head,  and  fed  upon  the  gypsy  larvae  with- 
out noticing  his  presence.  By  using  an  opera  glass  all  the 
motions  of  the  crow  in  searching  for  and  capturing  its  prey 
were  readily  seen.  The  crows  will  alight  upon  the  branches 
and  search  the  under  sides,  where  the  gypsy  moth  caterpil- 
lars crawl  or  cluster.  They  are  apparently  quite  fond  of  the 
pupae,  and  will  also  eat  the  female  moths.  The  young  crows 
kept  at  the  insectary  were  fed  almost  exclusively  for  two  or 
three  days  upon  these  insects.  Although  they  ate  them  at 
first  with  avidity,  they  soon  refused  them  and  would  not 
touch  them  so  long-  as  other  food  could  be  obtained  ;  neither 


218  THE   GYPSY  MOTH. 

would  they  capture  and  eat  the  larvae.  When  the  first  moths 
were  placed  in  the  cage,  they  caught  and  ate  them  eagerly. 
The  larger  crow  ate  eighty-three  and  the  smaller  thirty-three. 
On  the  second  trial,  crow  number  one  ate  fifty-eight  moths 
and  crow  number  two  twenty-three,  thus  together  destroying 
eighty-one.  On  the  third  trial  they  would  have  none  of  them. 
At  first,  the  birds,  being  apparently  quite  hungry,  devoured 
them  whole.  Later  they  rejected  the  thorax  with  the  wings 
and  other  appendages,  and  took  the  soft  abdomens  only. 
The  birds  were  at  first  so  eager  for  the  moths  that  they 
would  snatch  them  from  each  other.  A  curious  fact  about 
their  eating  was  that  they  swallowed  the  moths  hind  end 
first,  while  grasshoppers  were  always  swallowed  head  first. 
It  would  appear  from  this  limited  experiment  that  the  crows 
soon  became  tired  of  a  gypsy  moth  diet.  It  is  quite  prob- 
able that  unconfined  crows  would  tire  of  the  moth  as  food 
were  no  other  food  available.  Yet  from  the  frequency  of 
the  crow's  visits  to  the  infested  spots,  the  size  and  capacity 
of  the  stomach,  and  the  number  of  different  forms  of  the 
moth  eaten,  it  may  be  inferred  that  this  species  is  quite  use- 
ful in  destroying  the  gypsy  moth. 

Other  Useful  Birds. 

Bluebird.  —  In  1891  the  bluebird  was  often  seen  feeding 
on  the  larvae  and  pupae  of  the  gypsy  moth,  but  this  was  not 
noticed  in  the  ensuing  years,  and  in  1895  no  bluebirds  were 
seen  during  the  summer  in  the  infested  region.  When  blue- 
birds breed  in  or  near  an  infested  orchard,  they  will  no  doubt 
destroy  many  of  these  insects. 

Warblers.  — Although  certain  warblers  have  been  seen 
occasionally  to  capture  many  of  the  gypsy  caterpillars  and 
moths,  it  is  difficult  to  determine  by  observation  or  dissection 
how  useful  they  are  in  this  respect.  Owing  to  their  activ- 
ity, and  the  small  size  of  the  larvae  usually  taken  by  them, 
it  is  often  impossible  to  learn  the  species  or  the  number  of 
insects  which  they  eat.  The  great  vernal  flights  of  warblers 
through  the  infested  region  occur  in  May,  at  a  time  when 
the  larvae  of  the  gypsy  moth  are  very  small,  and  are  either 
feeding  or  resting  upon  or  underneath  the  leaves.  The  birds 
migrating  northward  restlessly  move  from  tree  to  tree,  and 


OTHER  USEFUL  BIRDS.  219 

accurate  observation  of  their  feeding  habits  is  then  difficult. 
As  warblers  glean  much  of  their  food  from  the  twigs  and 
foliage,  it  is  highly  probable  that  the  mortality  among  the 
small  caterpillars  is  partly  caused  by  these  birds. 

Observations  on  the  feeding  of  the  warblers  were  made 
when  the  spring  migrants  had  gone  north  and  the  sum- 
mer residents  were  breeding.  The  warblers  which  breed  in 
the  infested  districts  do  not  appear  to  feed  habitually  on  the 
gypsy  moth.  Both  observations  and  dissections  indicate  that 
most  of  them  prefer  the  small,  smooth,  geometrid  larvae.  All 
of  them  appear  to  have  a  particular  fondness  for  the  canker- 
worms,  and  a  few  eat  the  tent  caterpillar.  Yet  some  of  the  ob- 
servations made  show  that  certain  species  of  warblers  destroy 
many  of  the  larger  gypsy  caterpillars.  These  species  also 
destroy  moths,  both  male  and  female.  Mr.  Bailey  saw  a  yel- 
low warbler  take  two  large  gypsy  moth  larvae,  tear  them 
open  and  eat  out  the  body  contents,  leaving  the  skins  upon 
the  tree.  He  saw  a  black-and-white  creeping  warbler  just 
from  the  nest  capture  and  eat  seventeen  gypsy  moth  cater- 
pillars. All  of  them  were  pecked  open. 

Mr.  I.  C.  Green,  a  former  employee  of  the  Board,  consid- 
ers the  redstart  the  most  useful  of  all  birds  in  destroying  the 
gypsy  moth,  but  does  not  give  the  details  of  his  observations. 
This  species  has  been  seen  by  other  observers  to  feed  espe- 
cially on  the  male  moth,  which  it  often  captures  in  flight. 

The  oven  bird  is  mentioned  by  several  observers  as  feed- 
ing on  larvae  and  moths.  The  other  warblers  in  the  list 
have  seldom  been  seen  to  take  any  form  of  the  moth. 

Sparrows.  — Though  the  towhee  bunting  or  chewink  was 
not  seen  preying  on  the  gypsy  moth  prior  to  1895,  the 
observations  of  Mr.  Mosher  give  ample  proof  of  its  useful- 
ness in  this  respect,  especially  in  woodland  or  in  sprout- 
land  where  it  is  a  common  bird.  It  eats  readily  all  forms  of 
the  moth  excepting  the  eggs,  and  this  habit  has  been  fre- 
quently observed.  The  rose-breasted  grosbeak  and  indigo 
bird  occasionally  eat  the  larvae. 

Flycatchers. — All  the  flycatchers  which  breed  in  the  dis- 
trict are  given  in  the  list  of  birds  which  destroy  the  moth. 
Though  most  of  them  kill  a  great  many  moths,  they  proba- 
bly are  not  as  useful  as  most  other  birds  on  the  list,  as  they 


220  THE  GYPSY   MOTH. 

pursue  mainly  the  quick-flying  male  moths.  Experience  in 
trapping  male  moths  has  shown  that  ordinarily  their  capture 
has  little  effect  on  the  number  of  fertile  egg-clusters  in  a  badly 
infested  spot.  This  is  partly  because  most  of  the  male  moths 
find  their  mates  close  at  hand,  and  so  fertilize  females  before 
taking  any  extended  flight;  and  partly  because  the  male 
being  polygamous,  each  one  that  escapes  the  birds  may  fer- 
tilize several  females.  Yet  as  very  many  of  the  males  are 
caught  by  flycatchers,  this  may  account  for  the  scarcity  of 
males  and  the  number  of  infertile  egg-clusters  sometimes 
found  in  badly  infested  localities.  As  many  males  emerge 
before  the  females,  and  as  the  moth  lives  but  a  few  days 
in  the  perfect  form,  most  of 
the  males  usually  die  before  the 
females  all  emerge,  and  males 
are  comparatively  scarce  late 
in  the  season  even  in  a  badly 
infested  locality.  If  at  this 
time  the  flycatchers  and  their 
•'  young  frequent  an  infested  lo- 
cality, they  still  further  reduce 
the  number  of  surviving  male 
moths.  This  scarcity  of  male 

is  in  part  caused  by  the  flycatchers  and  other  birds,  may 
prevent  the  fertilization  at  that  time  of  many  eggs.  Yet  the 
good  done  in  this  way  by  the  flycatchers  may  be  counteracted 
by  their  destruction  of  hymenopterous  parasites  of  the  moth. 
Of  these  parasites  the  ichneumon  flies  appear  to  be  the 
most  useful,  yet  even  they  have  not  proved  at  all  effectual 
in  reducing  the  numbers  of  the  gypsy  moth,  even  under  the 
most  favorable  circumstances.  Mr.  Kirkland  has  seen  a  wood 
pewee  dart  down  and  capture  an  ichneumon  fly,  apparently 
TJieronia  melanocephala.  This  fly  sometimes  attacks  gypsy 
caterpillars,  and  has  been  frequently  seen  searching  over 
trees  infested  by  them.  Occasionally  a  flycatcher  will  pick 
up  a  spinning  larva  as  it  hangs  swaying  in  the  wind  by 
its  thread  from  the  tree,  but  there  seems  to  be  no  reason  to 
believe  that  this  is  a  habit.  Though  the  flycatchers  confine 
their  feeding  on  this  insect  mostly  to  the  male  moths,  they 


OTHER  USEFUL  BIRDS.  221 

frequently  take  females,  and  doubtless  destroy  many  in  the 
aggregate  during  a  season.  The  king  bird  appears  to  be  the 
most  useful  flycatcher  in  this  respect,  and  has  been  seen  to 
eat  very  many  of  the  females.  This  bird  may  thus  render 
efficient  service  to  the  farmer  by  preventing  the  deposit  of 
many  thousands  of  fertilized  eggs.  Its  comparative  value 
as  a  gypsy  moth  destroyer  depends  largely  upon  the  number 
of  female  moths  that  it  kills. 

Woodpeckers.  —  Of  these  most  useful  birds  the  three  resi- 
dent species  have  all  been  seen  feeding  upon  the  caterpillars 
or  pupae  of  the  moth. 

The  flicker  has  also  been  seen  carrying  caterpillars  to  its 
young.  Mr.  W.  C.  Colt,  an  inspector  in  the  employ  of  the 
Board,  says  that  he  watched  a  female  flicker  take  nearly  full- 
grown  larvae  to  its  young.  The  bird  made  regular  trips  to 
its  nest  at  intervals  of  from  three  to  five  minutes.  The 
downy  woodpecker  was  observed  by  Mr.  Bailey  to  eat  a  few 
caterpillars,  and  to  peck  many  others  and  afterward  drop 
them  from  the  tree  to  the  ground. 

From  what  is  known  of  the  habits  of  woodpeckers,  it  was 
expected  that  they  would  be  found  to  feed  on  the  gypsy 
moth  pupae.  The  downy  and  hairy  woodpeckers  are  known 
to  feed  in  winter  to  a  greater  or  less  extent  on  the  hibernat- 
ing pupae  of  many  insects.  Yet  the  hairy  woodpecker  only 
has  been  observed  to  peck  into  the  pupae  of  the  gypsy  moth. 
This  bird  is  not  at  all  common  in  the  district,  but  both 
old  and  young  birds  have  been  seen  feeding  upon  the  pupae 
by  Mr.  Mosher. 

There  is  much  difference  of  opinion  among  observers  as  to 
the  comparative  usefulness  of  certain  species  of  birds  in 
destroying  the  gypsy  moth.  This  is  to  be  expected,  as  each 
is  prone  to  regard  his  own  observations  as  conclusive  in 
respect  to  all  the  species  which  he  observes.  In  drawing 
conclusions  from  observations  on  the  food  of  birds  a  great 
deal  must  be  allowed  for  their  individual  preferences  and 
acquired  tastes.  For  example  :  several  observers  report  the 
red- eyed  and  yellow-throated  vireos  as  feeding  eagerly  on 
gypsy  moth  caterpillars.  Mr.  Henry  Shaw  notes  that  in 
one  infested  locality  the  red-eyes  appeared  to  be  living  on 
them,  eating  them  constantly.  Mr.  C.  E.  Wood  has  seen 


222  THE   GYPSY  MOTH. 

the  yellow-throat  go  from  burlap  to  burlap,  drawing  out  the 
larvae  from  beneath.  Yet  Mr.  Bailey  reports  that  he  has 
seen  individuals  of  these  species  search  a  tree  over  for  hair- 
less larvae  before  they  would  eat  one  of  the  caterpillars  of 
the  gypsy  moth,  of  which  there  were  thousands  on  the  tree. 
I  do  not  question  the  correctness  of  any  of  these  observa- 
tions. Certain  fowls  or  flocks  of  fowls  in  the  infested 
region  ate  the  caterpillars  with  avidity,  while  other  individ- 
uals or  flocks  would  not  touch  them.  The  same  individual 
preference  was  noticed  among  toads. 

It  appears  that  the  presence  of  a  great  number  of  hair- 
less larvae  has  the  indirect  effect  of  lessening  the  number  of 
gypsy  moth  caterpillars  destroyed  by  birds.  When  canker- 
worms  are  plentiful,  the  birds  eat  comparatively  few  of  the 
hairy  caterpillars  until  the  canker-worms  have  disappeared. 
Although  many  gypsy  moth  caterpillars  were  eaten  very 
early  in  the  season  of  1895  by  the  orioles,  vireos  and  other 
birds,  these  caterpillars  received  very  little  attention  later, 
when  the  growing  canker-worms  became  more  noticeable. 
Most  of  the  birds  then  devoted  their  attention  to  the  canker- 
worms.  About  June  10,  when  the  canker-worms  had  mostly 
disappeared,  the  birds  again  attacked  the  gypsy  moth  larvae 
and  continued  to  feed  upon  them  for  some  time.  Their  appe- 
tites for  these  insects  appeared  finally  to  wane,  having  been 
apparently  cloyed  by  an  excessive  diet  of  hairy  caterpillars. 
It  has  been  noticed  that  sometimes  birds  tire  of  a  monotonous 
diet,  and  that  they  will  even  cease  to  feed  for  a  time  upon  a 
favorite  insect  prey.  This  may  partially  account  for  the  fact 
mentioned  by  Grimm,  that  the  birds  forsook  the  Eussian 
forest  which  had  been  devastated  by  the  gypsy  moth.  Yet 
this  would  not  be  a  sufficient  reason  to  account  for  a  continued 
absence,  as  birds  often  return  to  feast  again  after  a  change  of 
diet.  But  the  lack  of  shade,  water  and  green  food,  all  of 
which  together  make  a  region  unfit  for  the  habitation  of  wood 
birds,  may  have  driven  them  for  a  time  from  the  devastated 
forest.  In  the  infested  district  in  Massachusetts  forest  birds 
will  not  remain  constantly  through  the  hot  summer  days  in 
woodland  which  has  been  stripped  by  the  gypsy  moth,  but 
will  betake  themselves  to  shaded  glades  and  brooksides,  mak- 
ing frequent  sallies  into  the  bare,  infested  woods  to  feed  on 
the  pest. 


BIRDS  FEEDING   ON  THE   MOTH.  223 


Birds  attracted  to  Infested  Localities. 

The  attraction  of  birds  to  infested  localities  and  the  num- 
bers of  gypsy  moths  destroyed  by  them  there  may  be  best 
realized  by  visiting  a  badly  infested  spot  at  a  season  when 
all  forms  of  the  insect  are  to  be  found  upon  the  trees.  At 
such  a  time  the  birds  which  feed  upon  the  moth  may  be 
observed  to  the  best  advantage.  For  this  purpose  one 
should  rise  before  daybreak  and  be  on  the  ground  before 
sunrise,  as  many  birds  are  in  active  pursuit  of  insects  at  that 
time. 

Upon  approaching  at  dawn  a  badly  infested  spot  in  wood- 
land, the  stroke  of  a  flitting  wing,  the  rustle  of  dead  leaves, 
an  occasional  shower  of  scattering  dewdrops,  a  chirp  or  alarm 
note  heard  here  and  there,  all  denote  the  presence  of  birds  in 
the  woods.  Their  forms  are  still  hidden  or  only  dimly  visible 
in  the  uncertain,  growing  morning  light.  The  infested  spot 
has  the  appearance  of  an  opening  or  clearing.  We  emerge 
in  what  appears  to  be  a  dead  forest.  The  trees  wear  no  foli- 
age. The  pines,  oaks,  birches,  poplars  and  wild  cherries  are 
stripped  and  bare.  The  few  leaves  which  still  hang  upon  the 
young  maples  and  walnuts  only  accentuate  the  general  naked- 
ness. There  are  sounds,  not  of  the  wind  or  storm,  and  yet 
akin  to  these,  pervading  the  woods,  —  sounds  as  of  dry 
leaves  stirred  by  a  rising  breeze,  mingled  with  those  of  the 
tine  pattering  raindrops  of  sudden  showers.  These  are  caused 
by  the  hosts  of  gypsy  caterpillars  which  have  devastated  the 
woods.  The  sound  of  their  feeding  is  in  the  air,  their 
excreta  rattle  like  raindrops  on  the  dead  leaves.  As  the 
rising  sun  throws  level  beams  across  the  hillside,  the  tracery 
of  the  bare,  interlacing  branches  and  twigs  is  reproduced 
upon  the  barren  upright  rocks  of  a  rugged  ledge.  There  is 
little  or  no  summer  green,  except  the  moss  on  the  stones 
along  the  stream,  and  a  few  small  shrubs  which  have  not 
yet  been  wholly  stripped.  Upon  the  bare  trees,  especially 
those  near  the  edges  of  the  defoliated  tract,  hundreds  of 
thousands  of  hairy  caterpillars  swarm.  Many  of  them  are 
now  hurrying  down  the  trunks  and  crawling  away  to  places 
of  concealment,  seeking  shelter  from  the  sun's  rays.  Many 
more,  having  been  travelling  perhaps  throughout  the  night 


224  THE  GYPSY  MOTH. 

in  search  of  food,  are  still  crawling  in  search  of  it,  either  on 
trees  or  upon  the  ground.  Masses  or  swarms  of  caterpil- 
lars are  clustered  in  every  sheltered  place ;  thousands  are 
feeding  on  the  leaves  of  trees  near  the  borders  of  the  deso- 
lated area.  The  pupae  hang  in  bunches  under  the  limbs 
and  in  the  crevices  of  the  larger  trees.  Many  female  moths 
are  just  emerging  from  the  chrysalides,  and  others  are  drying 
their  wings.  This  is  the  appearance  presented  by  a  wood- 
land colony  of  the  gypsy  moth  on  a  July  morning. 

Seated  here,  somewhat  screened  by  the  remaining  herbage 
on  the  borders  of  the  stripped  tract,  we  may  observe  the 
struggle  for  existence  between  the  moth  and  other  forms 
of  life.  From  the  harsh  semi-conversational  notes  heard, 
first  solemn  and  wary,  then  growing  animated  and  cheerful, 
we  judge  that  a  crow  is  feeding  its  fledged  young  in  the 
vicinity.  Soon  the  crows  are  seen  flying  near.  They  alight 
about  forty  yards  away  by  the  brook,  and  the  old  bird,  go- 
ing to  a  clump  of  bushes,  feeds  her  young  time  after  time 
with  something  she  takes  from  among  the  stems.  With 
a  glass  we  can  see  her  take  the  larvae  and  pupae  and  put 
them  into  the  open  beaks  of  her  eager  young.  The  old  bird 
now  finds  a  female  moth  and  passes  it  to  one  of  the  brood. 
Soon  becoming  alarmed  by  some  movement  on  our  part,  they 
fly  away  to  some  pines,  where  in  the  high  branches  they 
resume  their  feeding.  An  examination  of  the  bushes  they 
have  just  left  shows  that  the  old  crow  has  taken  nearly  all 
the  larvae,  pupae  and  moths  from  the  clump,  leaving  only  a 
few  moult  skins  and  spun  threads  to  mark  the  recent  ex- 
istence of  the  moth  there. 

A  family  of  chickadees  now  appear.  Flitting  about 
among  the  trees,  they  begin  to  catch  and  eat  the  larvae.  One 
picks  up  a  large  caterpillar,  places  both  feet  upon  it  and  eats 
out  the  viscera,  leaving  the  head  and  skin.  Another  pecks 
a  caterpillar  into  small  pieces  and  apparently  eats  most  of  the 
pieces.  Number  one  now  flies  some  ten  yards  with  a  large 
larva  which  it  has  just  seized.  Alighting  on  a  convenient 
limb,  the  bird  hammers  its  prey  awhile  and  finally  drops  it, 
mutilated  and  dying,  to  the  ground.  Another  bird  tears  a 
female  moth  in  pieces,  eating  only  the  contents  of  the  abdo- 
men. All  devote  more  or  less  time  to  killing  the  pupae,  eat- 


BIKDS   FEEDING   ON   THE   MOTH.  225 

ing  only  a  small  portion  of  each.      Thus  with  cheery  chirp 
and  call  they  flit  about  through  the  woods,  killing  and  eat- 
ing as  they  go.     A  red-eyed  vireo  alights  on  a  branch  within 
six  feet  of  us,  and,  picking  three  half-grown  larvae  from  the 
leaves,  swallows  them  head  first  and  flies  away  towards  the 
brook.     Something  is  scratching  in  the  leaves  a  few  yards 
away.     With  the  glass  we  can  see  four  towhees  scratching 
and  digging  like  chickens.    They  are  searching  for  the  pupae 
which  they  greedily  eat.     If  a  male  moth  flies  low  overhead, 
one  of  these  birds  will  leap  from  the  ground  and  capture  it. 
They  search  about  upon  the  ground  and  among  the  small 
shrubs  and  seize  the  newly  emerged  females,  beating  them 
on  the  ground  and  finally  swallowing  them.     A  lone  cuckoo 
whose  dismal  notes  we  have  just  heard  now  comes  down 
from  a  near-by  tree,  alights  on  a  small  sapling  and  proceeds 
to  breakfast.     It  picks  off  fourteen  caterpillars,  one  by  one, 
hammers  the  larger  ones  a  little  and  then  swallows  them 
whole.     A  family  of  brown  thrushes  is  busy  by  the  brook. 
With  the  glass  one  of  them  can  be  plainly  seen  in  the  act 
of  taking  pupae  from  the  stem  of  one  of  the  larger  bushes. 
A  family  of  five  black-and-white  creeping  warblers  come  in 
sight.    They  run  and  climb  about  on  the  trunks  and  branches 
of  the  stripped  trees,  picking  up  the  smaller  larvae  of  the 
gypsy  moth  and  other  insects,  and  now  and  then  darting  into 
the  air  after  flying  male  moths  or  pecking  at  the  females. 
These  females  they  rarely  eat  and  sometimes  do  not  mate- 
rially injure,  though  they  knock  many  of  them  off  the  trees. 
One  female  which  falls  is  snapped  up  by  a  towhee  which 
springs  from  the  ground  to  take  it  in  the  air.       A  single 
Baltimore  oriole  flies  in,  looks  about  as  if  out  of  its  element, 
catches  several  larvae  and  disappears  in  the  direction  of  the 
highway.     The  harsh  cries  of  the  blue  jays  have  been  ring- 
ing for  some  time  through  the  woods.     One  at  a  time,  five 
jays  pass  among  the  trees.     With  the  glass  we  can  see  two 
of  them  taking  the  large  larvae  from  a  tree  trunk.      They 
fly  with  them  to  branches  or  to  the  ground,  and  eat  them 
there.      You  can  plainly  see  the  jays  as  they  take  the  cater- 
pillars in  their  bills,  but  they  are  so  shy  that  they  will  not 
remain  long  within  our  range  of  vision.     Now  the  chicka- 
dees are  back  again.      One  of  them  takes  twelve  pupae  in 


226  THE   GYPSY  MOTH. 

succession,  carries  each  one  to  a  limb,  pecks  it  open  and 
drops  it  upon  the  ground. 

As  the  sun  grows  warmer  the  number  of  male  moths  in 
zigzag  flight  increases.  It  is  now  six  o'clock,  and  the  snap- 
ping of  bills  heard  on  all  sides  tells  us  that  the  flycatchers 
are  in  the  woods.  Seven  king  birds  are  hunting  the  male 
moths.  They  catch  scores  of  them,  and  occasionally  they 
pick  off  a  female  or  capture  a  falling  larva.  One  of  these 
birds  comes  in  over  the  tree  tops  and  hangs  suspended  on 
hovering  wings.  Suddenly  dropping  toward  the  earth,  it 
picks  up  a  fluttering  female  moth,  and,  flying  to  a  limb,  with 
a  single  snap  of  the  bill  divests  the  insect  of  both  wings  and 
swallows  it.  The  bird  then  looks  to  right  and  left,  flies  from 
its  perch,  catches  a  male  moth  in  mid-air,  returns  to  its  perch, 
swallows  the  moth  and  calls  cheerily  to  its  mate.  The  other 
king  birds  are  all  busy  in  like  manner.  As  they  seem  to  have 
settled  down  to  remain  for  some  time,  we  will  keep  tally  of 
such  moths  as  we  can  actually  see  them  take  at  close  range. 
Several  chipping  sparrows  now  appear  hopping  about  on  the 
ground.  Now  and  then  one  picks  up  a  half-grown  larva. 
They  are  pecking  and  eating  the  female  moths.  They  also 
chase  and  capture  a  low-flying  male  moth.  Two  catbirds 
are  searching  the  thicket  along  the  brook.  They  are  taking 
pupa3  from  the  ground  and  dead  leaves  and  also  from  the 
leaves  and  twigs  of  the  low  bushes,  but  we  can  see  this  only 
occasionally,  as  most  of  the  time  the  birds  are  hidden  from 
view.  The  crows  went  when  the  king  birds  came,  but  the 
flycatchers  are  still  hawking  about.  As  the  reflected  heat 
of  the  summer  sun  is  radiated  from  the  earth,  the  newly 
emerged  male  moths  gain  life  and  vigor  from  its  warmth, 
and  fly  in  large  numbers  through  the  woods.  Three  least 
flycatchers,  two  phrebes  and  several  wood  pewees  are  in  sight 
and -pursue  the  moths  most  of  the  time. 

At  half-past  nine  the  king  birds  have  disappeared.  Our 
tally  sheet  shows  that  we  have  seen  them  take  seventy-nine 
male  and  twenty-four  female  moths.  They  were  watched 
only  a  portion  of  the  time,  but  were  feeding  quite  constantly. 
It  is  safe  to  say  that  between  6.15  and  9.30  they  have  killed 
two  hundred  and  fifty  male  moths.  The  number  of  females 
taken  cannot  be  so  readily  estimated. 


BIRDS   FEEDING  ON  THE  MOTH.  227 

One  chipping  sparrow  has  been  seen  to  take  five  females ; 
six  least  flycatchers,  thirty-one  males  and  nine  females  ;  two 
wood  pewees,  twenty-two  males  and  seven  females.  These 
birds  were  most  of  the  time  at  a  considerable  distance  from 
the  point  of  observation,  and  it  was  only  now  and  then  when 
they  approached  quite  near  that  their  actions  could  be  dis- 
tinctly seen.  The  phoebe  appears  to  have  taken  male  moths 
only.  The  towhees  took  eighteen  moths,  male  and  female, 
while  on  the  ground.  They  then  went  into  the  trees,  and 
while  there  moved  on  and  were  lost  to  view.  A  male  yellow 
\varbler  appeared  and  was  seen  to  eat  a  larva  and  a  female 
moth.  The  oriole  came  again,  taking  four  larvae.  Redstarts, 
creeping  warblers  and  chickadees  come  and  go,  feeding  on 
the  moth,  but  it  is  impossible  to  follow  them  and  also  watch 
the  other  birds.  It  is  now  eleven  o'clock.  The  birds  have 
nearly  all  left  the  hot  and  barren  land  of  the  defoliated  hill- 
side, and  are  resting  or  feeding  quietly  in  the  shade  among 
the  leaves,  where  they  cannot  be  so  readily  watched. 

Let  us  now  go  to  an  infested  orchard  a  mile  away,  where 
not  all  the  trees  have  been  stripped  by  the  caterpillars.  Here 
we  find  some  species  of  birds  represented  that  were  seen  in 
the  morning  in  the  woods,  but  the  catbird,  the  towh.ee,  the 
creepers,  the  redstart,  the  wood  pewee  and  the  crow  are 
absent.  Yet  we  find  here  the  robin,  bluebird,  yellow- 
throated  vireo,  flicker  and  house  wren,  all  of  which  feed 
more  or  less  upon  the  moth.  As  the  afternoon  advances, 
seven  black-billed  and  four  yellow-billed  cuckoos  are  seen 
feeding  on  the  larvre  and  pupse.  There  are  yellow  warblers, 
chickadees,  half  a  dozen  orioles,  several  chipping  sparrows 
and  other  birds  in  the  orchard.  The  few  infested  orchard 
trees  appear  to  be  much  better  protected  by  birds  than  the 
woodland,  and  the  moth  has  not  made  so  much  progress 
here. 

In  the  waning  summer  afternoon  we  return  to  the  woods, 
where,  as  the  shadows  lengthen,  the  birds  again  are  busy. 
The  king  birds  and  other  flycatchers  and  the  chickadees  are 
especially  diligent.  The  king  birds  are  now  eating  many 
of  the  female  moths.  A  solitary  scarlet  tanager  hammers 
a  female  moth  upon  a  branch,  shearing  off  its  wings  and 
then  eating  its  abdomen.  In  the  advancing  shadows  of  the 


228  THE   GYPSY   MOTH. 

approaching  night  many  sparrows  are  seen  hopping  along 
the  ground,  where  they  find  their  evening  meal.  Although 
the  birds  are  quite  silent  and  it  is  impossible  to  make  out  the 
species  as  they  move  among  the  shadows,  the  white  female 
moths  can  be  plainly  seen  as  the  birds  pick  them  up  in  their 
bills.  Some  fifty  birds  are  seen  busily  feeding  on  the  moth 
as  we  walk  through  the  stripped  woodland  once  more  before 
leaving  for  the  night.* 

Birds  which  destroy  the   Various  Forms  of  the  Moth. 

The  birds  which  have  been  found  preying  upon  the  gypsy 
moth  may  be  classified  as  follows  :  — 

Birds  feeding  on  the  larvse  —  chickadee,  downy  wood- 
pecker, wood  thrush,  yellow-billed  cuckoo,  black-billed 
cuckoo,  yellow  warbler,  rose-breasted  grosbeak,  scarlet  tana- 
ger,  black-and-white  creeping  warbler,  red-eyed  vireo,  chip- 
ping sparrow,  oriole,  blue  jay,  yellow-throated  vireo,  crow, 
catbird,  black-throated  green  warbler,  redstart,  wood  pewee, 
robin,  English  sparrow,  least  flycatcher,  wren,  Maryland 
yellow-throat,  chestnut-sided  warbler,  brown  thrush,  purple 
grackle,  oven  bird,  white-eyed  vireo,  bluebird,  flicker. 

Birds  feeding  on  the  pupae — yellow-billed  cuckoo,  black- 
billed  cuckoo,  chickadee,  yellow-throated  vireo,  towhee,  hairy 
woodpecker,  scarlet  tanager,  crow,  catbird,  oriole,  blue  jay, 
phoebe,  English  sparrow,  brown  thrush,  king  bird,  wood 
pewee,  bluebird,  yellow  warbler. 

Birds  feeding  on  the  male  moths  —  king  bird,  chickadee, 
oriole,  redstart,  yellow  warbler,  towhee,  wood  pewee,  yellow- 
throated  vireo,  red-eyed  vireo,  great-crested  flycatcher,  black- 
and-white  creeping  warbler,  least  flycatcher,  phoebe,  brown 
thrush,  oven  bird,  English  sparrow,  chipping  sparrow,  blue- 
bird, indigo  bird. 

Birds  feeding  on  the  female  moths  —  king  bird,  chicka- 
dee, towhee,  great-crested  flycatcher,  phcebe,  black-and-white 
creeping  warbler,  red-eyed  vireo,  crow. 

Birds  which  possibly  eat  the  eggs  —  downy  woodpecker, 
chickadee,  white-breasted  nuthatch,  blue  jay,  English  spar- 
row. 

*  This  description  of  the  feeding  of  birds  upon  the  gypsy  moth  is  taken  from 
notes  made  in  the  field. 


BIRDS  FEEDING   ON  THE  MOTH.  229 

Do  Birds  feed  on  the  Eggs  of  the  Moth? 

The  field  agents  employed  in  the  gypsy  moth  work  have 
often  noticed  egg-clusters  of  the  moth  which  appeared  to 
have  been  pecked  open  by  birds.  A  large  number  of  egg- 
clusters  in  the  woods  presented  this  appearance.  Occasion- 
ally a  bird  was  seen  apparently  pecking  or  eating  the  eggs. 
A  single  species  which  would  feed  on  the  eggs  during  all  the 
winter  months  would  be  far  more  useful  than  many  feeding 
on  the  caterpillars  during  the  summer.  The  eggs  are  so 
minute  that  a  bird  feeding  on  them  would  destroy  in  one  day 
more  individuals  of  the  species  than  another  could  in  one 
hundred  days  by  feeding  on  the  large  caterpillars.  It  could 
find  these  eggs  for  nine  months  of  the  year,  whereas  the  cat- 
erpillars are  to  be  found  for  less  than  five  months.  The  de- 
struction of  the  eggs  also  prevents  all  injury  to  vegetation 
by  the  caterpillars,  while  if  the  eggs  are  allowed  to  hatch, 
the  caterpillars  may  do  considerable  damage  before  they  are 
killed. 

Wishing  to  do  all  possible  toward  protecting  and  fostering 
egg-eating  birds,  I  determined  to  learn  by  accurate  observa- 
tion and  dissection  whether  any  of  our  native  birds  were 
destroying  any  considerable  number  of  the  eggs.  For  this 
purpose  Mr.  Bailey  was  requested  to  watch  birds  during  a 
part  of  the  winter  of  1894-95.  He  selected  several  stations 
for  observation,  one  in  an  orchard  and  others  in  the  woods  of 
the  Middlesex  Fells.  The  stations  in  the  woods  were  chosen 
because  of  the  abundance  of  the  egg-clusters  of  the  gypsy 
moth  in  the  vicinity  of  each.  The  station  in  the  orchard 
was  surrounded  by  a  high  board  fence,  built  to  prevent  in- 
terference from  without,  and  several  hundred  egg-clusters  of 
the  gypsy  moth  were  exposed  on  a  single, tree.  At  all  these 
stations  bait  was  hung  upon  the  trees  for  the  purpose  of 
attracting  birds.  Pieces  of  beef  bone,  suet,  waste  meat  and 
grain  were  used  to  attract  the  different  species.  Crows,  jays, 
nuthatches,  titmice,  kinglets,  woodpeckers  and  tree  creepers 
soon  found  the  bait  and  made  frequent  visits  to  the  infested 
trees. 

The  birds  soon  became  so  accustomed  to  the  presence  of 
the  observer  that  they  would  feed  within  a  few  feet  of  him. 


230  THE   GYPSY  MOTH. 

The  chickadees  became  so  tame  that  they  would  sometimes 
alight  upon  his  hat  or  coat  sleeve.  They  would  come  like  a 
flock  of  chickens  to  be  fed,  and  some  would  feed  on  limbs 
within  three  feet  of  his  face.  Occasionally  one  would  even 
take  food  from  his  hand.  In  a  short  time  chickadees,  nut- 
hatches, creepers  and  downy  woodpeckers  became  so  tame 
that  their  feeding  habits  could  be  closely  watched.  Then 
observations  were  begun.  A  downy  woodpecker  was  seen 
to  strike  an  egg-cluster,  scattering  the  eggs  over  the  snow ; 
yet  the  bird  did  not  eat  any  of  them.  On  close  examination 
it  was  seen  that  the  eggs  as  well  as  some  of  the  bark  on 
which  they  rested  had  been  removed  by  the  bird  to  get  at 
the  larva  of  some  insect  which  happened  to  lie  under  this 
bark.  The  birds  which  came  to  the  bait  on  the  infested  trees 
were  there  many  times  each  day  for  about  three  months,  yet 
the  eggs  were  seldom  molested.  During  all  this  time,  how- 
ever, the  birds  were  feeding  daily  on  eggs  and  other  hibernat- 
ing forms  of  other  injurious  insects,  of  which  they  destroyed 
large  numbers.  Thirty-eight  visits  were  made  in  one  after- 
noon by  birds  to  one  tree  on  which  were  sixty-five  gypsy 
egg-clusters.  The  birds  all  came  within  three  or  four  feet 
of  these  eggs ;  two  of  them  even  perched  on  egg-clusters, 
but  they  did  not  eat  or  even  notice  the  eggs.  Whether  the 
result  would  have  been  the  same  had  there  been  no  meat  for 
them  to  feed  on,  we  cannot  say  ;  yet,  as  they  were  constantly 
destroying  the  eggs  of  other  insects,  and  as  they  occasionally 
pecked  the  egg-clusters  of  the  gypsy  moth  but  did  not  eat 
the  eggs,  it  is  fair  to  assume  that  they  will  not  do  so  unless 
perhaps  '  when  driven  to  it  by  extreme  hunger.  As  from 
observations  made  on  birds  in  confinement  it  seemed  prob- 
able that  the  hairs  with  which  the  egg-clusters  are  covered 
were  disagreeable  to  the  birds,  an  experiment  was  made  to 
see  if  they  would  eat  the  eggs  when  the  hair  was  removed. 
For  this  purpose  some  hundreds  of  eggs  denuded  of  hair 
were  glued  upon  a  twig  or  stick  in  close  proximity  to  the 
meat.  The  birds  attacked  the  bait  as  usual,  but  if  they 
ate  any  of  the  eggs  it  was  not  observed,  although  a  few 
were  knocked  or  pecked  off.  They  would  not  eat  the  eggs 
even  when  they  were  cleaned  of  hair  and  distributed  over 
the  meat.  No  birds  were  actually  seen  to  eat  any  of  the 


BIRDS   FEEDING  ON  THE  MOTH.  231 

eggs.  One  hundred  and  ninety-one  egg-clusters  were  put 
upon  a  tree  to  which  from  ten  to  thirty  chickadees  canie 
daily.  Only  seventeen  of  these  clusters  were  pecked  open. 
In  each  case  the  bird  was  seen  in  the  act.  The  eggs  were 
pecked  off  or  taken  in  the  beak  and  dropped  to  the  ground. 
A  few  blows  would  generally  suffice  to  knock  off  most  of 
the  eggs.  Ten  birds  which  were  pecking  at  the  eggs  were 
shot,  but  in  no  case  were  either  the  eggs  or  any  portions  of 
them  found  in  the  stomach  or  intestines. 

The  observations  showed  that  the  egg-clusters  were  some  • 
times  pecked  off  by  nuthatches,  either  in  a  search  for  hiber- 
nating larvae  or  pupae  hidden  beneath  the  clusters,  or  to 
secure  the  larvae  of  predaceous  insects  which  bore  into  the 
egg-clusters  and  feed  upon  the  eggs.  No  bird  has  actually 
been  proved  to  feed  upon  the  eggs  except  the  English  spar- 
row. One  of  these  birds  which  was  kept  in  confinement  ate 
a  few  of  these  eggs  from  time  to  time  when  deprived  of 
other  food,  but  did  not  appear  to  relish  them.  It  appears 
that  very  little  can  be  expected  from  our  native  birds  in  this 
respect,  unless  they  acquire  a  taste  for  the  eggs.  Yet  many 
egg-clusters  have  been  found  which  appear  to  have  been 
pecked  open  or  eaten  by  birds.  The  cause  of  this  appear- 
ance was  sought,  and  it  was  seen  that  squirrels  and  wood- 
peckers when  climbing  about  on  the  trunks  and  branches 
of  trees  frequently  tore  off  the  eggs  in  running  or  climbing 
over  them,  so  that  they  presented  much  the  same  appearance 
as  those  actually  pecked  into  by  birds.  The  gray  and  red 
squirrels  were  seen  in  the  act,  as  well  as  several  species  of 
birds.  Chickadees  have  frequently  been  seen  by  men  em- 
ployed in  the  woods  to  peck  these  egg-clusters,  and  several 
observations  seemed  to  indicate  that  birds  were  feeding  on 
them.  The  woodpeckers  occasionally  knocked  them  off  the 
trees.  Considering  the  prying,  thieving  nature  of  the  jays, 
it  is  quite  probable  that  they  may  peck  into  the  egg-clusters 
and  eat  the  eggs.  Though  the  eggs  are  so  tough  that  the 
smaller  titmice  might  have  difficulty  in  breaking  their  shells, 
the  more  powerful  beak  of  the  jay  would  easily  accomplish 
this. 

In  Europe,  woodpeckers,  creepers  and  titmice  are  said  to 
perform  great  service  by  eating  the  eggs  of  the  gypsy  moth. 


232  THE   GYPSY  MOTH. 

Altum  says  that  in  the  year  1848  endless  numbers  of  the 
larvse  of  the  gypsy  moth  had  eaten  every  leaf  from  the  trees 
of  Count  Wodzicki.  In  the  fall  all  the  trunks  and  branches 
were  covered  with  the  egg-clusters.  Having  recognized  the 
uselessness  of  the  attempt  to  remove  them  by  hand,  he  finally 
gave  up  all  his  endeavors,  and  prepared  to  see  his  beautiful 
trees  die.  Toward  winter  numerous  flocks  of  titmice  and 
wrens  came  daily  to  the  trees.  The  egg-clusters  disap- 
peared. In  the  spring  twenty  pairs  of  titmice  nested  in  the 
place,  and  the  caterpillar  plague  was  noticeably  reduced.  In 
the  year  1850  the  birds  had  so  cleared  his  trees  that  he  saw 
them  during  the  entire  summer  in  their  most  beautiful 
verdure.* 

Reaumur  says  that  the  larvse  of  the  gypsy  moth  were  very 
numerous  in  1826  on  the  lines  of  the  Allee  Verteat  Brussels. 
Many  of  the  trees  were  stripped,  and  if  one-half  the  eggs 
which  were  deposited  that  year  had  hatched,  scarcely  a  leaf 
would  have  been  left  the  next  season,  either  there  or  in  the 
park,  where  the  eggs  were  numerous  also ;  yet  two  months 
afterward  hardly  one  was  to  be  seen.  This  destruction  of 
the  eggs  he  attributes  to  titmice,  tree  creepers  and  other 
small  birds,  f 

The  Introduction  of  European  Birds. 

If  it  is  true  that  these  European  birds  are  so  very  useful 
in  this  respect,  the  comparative  immunity  of  many  European 
regions  from  the  attacks  of  the  gypsy  moth  may  be  due  in  a 
measure  to  their  efforts.  If  such  be  the  case,  their  introduc- 
tion into  Massachusetts  may  well  be  thoughtfully  considered. 
If  introduced  into  a  new  country  these  feathered  egg  hunters 
might  thrive  and  multiply  exceedingly,  and  if  the  eggs  of 
the  gypsy  moth  are  to  them  a  familiar  food,  they  would 
probably  seek  these  eggs  here  in  preference  to  the  unfamiliar 
insect  eggs  which  they  would  find.  Such  birds  might  in  this 
way  prove  as  useful  as  a  small  army  of  men.  Yet  what  com- 
pensation would  they  exact  for  this  service  ? 


*  "  Forstzoologie,"  Vol.  II.,  page  324,  1880. 

t  "An  Introduction  to  Entomology,"  by  Kirby  and  Spence,  Philadelphia,  1846, 
page  152. 


INTRODUCTION  OF  FOREIGN  BIRDS.       233 

When  the  introduction  of  any  bird  or  other  animal  from  a 
foreign  country  is  proposed,  great  care  should  be  exercised  to 
study  thoroughly  all  phases  of  the  subject.  Often,  when 
such  importations  have  been  made  without  careful  scientific 
investigation,  they  have  proved  very  expensive  mistakes. 
The  importation  of  the  rabbit  into  Australia,  the  mongoose 
into  Jamaica,  and  the  sparrow  into  America  and  Australia, 
are  familiar  examples.  The  English  sparrow  was  introduced 
here  for  the  express  purpose  of  suppressing  such  native 
pests  as  the  larvae  of  the  canker-worm  moths.  If  previous 
to  its  introduction  its  habits  had  been  carefully  studied  in 
Europe  by  a  competent  man  appointed  for  the  purpose  by  the 
United  States  government,  its  introduction  might  have  been 
prevented.  This  exotic  species,  the  value  of  which  is  doubted 
in  its  native  home,  was  brought  here  to  perform  a  task  which 
native  American  species  might  have  accomplished  much  bet- 
ter had  they  been  protected  and  encouraged  in  our  parks  as 
the  sparrow  was. 

There  are  in  Europe  at  least  six  different  species  of  titmice. 
All  of  tKem  are  found  in  some  of  the  countries  where  dispar 
is  native.  They  are  all  recognized  as  eminently  beneficial, 
and  are  regarded  by  foresters,  entomologists  and  ornitholo- 
gists as  among  the  most  useful  species  in  controlling  noxious 
insects.  Could  they  be  successfully  introduced  here,  they 
might  do  a  vast  amount  of  good  not  only  in  destroying  the 
eggs  of  the  gypsy  moth  but  the  larvae  also,  as  well  as  the 
eggs  of  many  other  injurious  insects.  It  is  difficult  to  imag- 
ine that  any  harm  could  come  from  the  introduction  of  these 
insectivorous  birds,  unless  they  should  change  their  habits 
in  some  way  or  drive  out  our  native  species,  especially  the 
black-cap  titmouse  or  chickadee,  and  fail  to  eat  the  females 
and  eggs  of  the  canker-worm  moths  which  the  chickadee 
devours  in  such  quantities.*  If  that  should  happen,  it 
would  indeed  be  a  catastrophe,  as  the  chickadee  is  one  of 
the  most  useful  of  all  our  native  birds. 

No  importation  of  birds  should  be  blindly  attempted.     An 


*  The  great  titmouse  (Parus  major)  has  been  known  to  attack  other  birds 
and  break  open  their  skulls,  eating  their  brains.  Some  species  of  European  tit- 
mice are  believed  to  do  some  injury  to  plantations  of  young  trees  by  destroying 
buds  or  leaves. 


234  THE   GYPSY  MOTH. 

exhaustive  study  of  their  food  habits  should  first  be  made 
in  their  native  home,  and  all  the  possibilities  of  their  intro- 
duction should  be  well  considered. 

The  English  Sparrow  and  the  Gypsy  Moth. 

The  English  sparrow  has  been  seen  to  feed  on  all  forms 
of  the  gypsy  moth ;  yet  this  bird  in  its  relations  to  dispar 
is  injurious  rather  than  beneficial  to  man.  That  its  name 
appears  so  frequently  in  the  records  of  observations  is  due  to 
the  fact  that  it  has  been  for  years  the  most  common  bird  in 
villages  and  cities  of  the  infested  region,  and  that  it  is  known 
to  many  observers  who  would  be  unable  to  identify  most 
other  birds. 

The  sparrow  was  introduced  into  Boston  Common  in  1868. 
It  is  recorded  that  in  1871  it  had  reached  Somerville,  and 
in  1873  Lynn  and  Cambridge.  It  undoubtedly  appeared  in 
Medford  about  the  same  time,  as  Somerville  adjoins  both 
Medford  and  Cambridge,  while  Lynn  is  some  ten  miles  east 
of  Boston.* 

While  it  is  no  doubt  true  that  native  birds  were  a  great 
factor  in  holding  the  moth  in  check  during  the  first  eight  or 
ten  years  of  its  existence  in  this  country  when  its  numbers 
were  few,  it  is  equally  true  that  the  rapid  distribution  and 
increasing  numbers  of  the  English  sparrow  later  from  1875 
to  1885  in  the  region  infested  resulted  in  driving  out  many 
native  birds.  The  bluebirds,  wrens,  house  swallows  and 
martins  were  the  first  to  leave,  for  as  the  sparrows  multiplied 
they  took  by  force  the  bird  houses  and  cavities  formerly  occu- 
pied by  these  birds,  compelling  them  to  seek  nesting-places 
elsewhere.  As  the  sparrows  further  multiplied,  their  quarrel- 
some disposition  impelled  them  to  attack  and  drive  away  other 
birds  found  around  their  nesting-places.  What  they  could 
not  do  singly  they  accomplished  by  force  of  numbers,  until 
comparatively  few  native  birds  were  able  to  breed  in  the 
immediate  vicinity  of  the  towns  and  villages.  It  is  undoubt- 
edly true  that  the  sparrow  did  something  toward  compensat- 

*  See  "  The  English  sparrow  in  America,"  United  States  Department  of  Agricult- 
ure, 1889,  page  21.  I  am  informed  by  Mr.  Walter  Wright  of  Medford  that  his 
father,  Elizur  Wright,  liberated  several  pairs  of  sparrows  in  Medford  about  that 
time. 


THE  ENGLISH   SPAEROW.  235 

ing  for  this  exile  of  insect-eating  birds  by  destroying  some 
of  the  smaller  gypsy  caterpillars  and  occasionally  killing 
some  moths  or  even  eating  a  few  moth  eggs;  but  it  was 
noticeable  that  wherever  the  sparrow  was  most  plentiful  in 
the  infested  region,  there  also  the  gypsy  moth  became  most 
numerous.  This  was  due  partly  to  a  distribution  of  both 
species  along  the  same  highways  and  partly  to  the  indirect  pro- 
tection extended  by  the  sparrow  to  the  moth  in  driving  away 
the  latter's  enemies  among  native  birds.  The  caterpillars  used 
the  bird  boxes  occupied  by  the  sparrows  as  a  place  of  retreat, 
and  the  female  moths  deposited  their  eggs  in  these  boxes. 
Sparrows  and  caterpillars  formed  a  sort  of  happy  family  in 
the  bird  houses,  which  swarmed  with  both  birds  and  insects. 
By  driving  the  native  birds  away  the  sparrow  became  in  a 
measure  responsible  for  the  phenomenal  increase  of  the  gypsy 
moth  in  numbers  and  its  consequent  destructiveness  in  Med- 
ford.  The  increase  of  some  other  injurious  insects  has  been 
noticed  wherever  the  sparrow  has  become  so  plentiful  as  to 
banish  native  birds.*  The  trees  in  Boston  and  some  of  the 
towns  in  its  vicinity  have  often  suffered  injury  from  invasions 
of  the  Orgyia  leucostigma,  or  white-marked  tussock  moth, 
caused  indirectly  by  this  sparrow.  The  sparrow,  having 
driven  away  the  native  birds,  fails  to  make  good  their  loss 
by  destroying  the  hairy  caterpillars. 

The  ravages  of  leaf-feeding  beetles  (  Chrysomela  scalar  is) 
have  also  become  noticeable  upon  elm  trees  in  localities  most 
frequented  by  the  sparrow.  The  imported  elm-leaf  beetle 
(Galeruca  xanthomelcena)  has  also  been  most  injurious  in 
cities  where  the  sparrow  is  abundant. 

The  Distribution  of  the  Moth  by  Birds. 
The  dissemination  of  the  moth  in  woodlands  seems  to  indi- 
cate that  it  is  distributed  more  or  less  by  birds.  This  theory 
is  substantiated  by  our  observations.  Isolated  colonies  of 
the  moth  are  sometimes  found  in  the  vicinity  of  the  nests 
of  the  larger  land  birds,  such  as  crows,  jays  and  robins. 
Occasionally  birds  flying  to  their  nests  with  food  for  their 


*  Second  report  on  the  "  Injurious  and  other  insects  of  the  State  of  New  York," 
by  J.  A.  Linter,  Albany,  1885,  pages  80-82. 


236  THE   GYPSY  MOTH. 

young  drop  caterpillars  or  other  insects.  We  have  a  few 
instances  on  record  where  the  gypsy  moth  caterpillars  have 
been  dropped  in  this  way,  and  in  one  case  at  least  the  cater- 
pillar was  not  materially  injured. 

Inspector  Sanderson  saw  a  wood  thrush  take  a  large  cater- 
pillar from  a  tree  and  fly  off  with  it.  The  caterpillar  wrig- 
gled in  the  bird's  bill  and  finally  fell  when  the  bird  had  flown 
a  few  yards.  The  bird  did  not  come  back  for  it. 

On  July  6,  1895,  Mr.  Bailey  saw  a  blue  jay  flying  over  the 
woods  in  Saugus.  It  was  flying  about  thirty  yards  from  the 
earth,  and  appeared  to  be  making  quite  a  long  flight.  As  it 
came  near  him  he  observed  that  it  was  carrying  something 
in  its  beak,  and  he  immediately  shot  at  it  with  his  revolver, 
not  with  the  intention  of  killing  the  bird,  but  to  make  it 
drop  what  it  was  carrying.  It  dropped  a  large  gypsy  moth 
caterpillar,  very  nearly  full  grown.  Mr.  Bailey  picked  up 
the  caterpillar,  which  appeared  to  be  uninjured.  He  had 
watched  the  bird's  flight  for  some  distance,  and  thought  it 
came  about  half  a  mile.  The  bird  continued  its  flight  north- 
ward, carrying  the  remainder  of  the  food  in  its  bill.  Mr. 
Bailey  kept  and  fed  the  larva,  which  pupated  on  July  12. 
A  female  moth  emerged  from  the  pupa  on  July  29,  appar- 
ently in  fine  health. 

It  is  not  an  uncommon  occurrence  for  birds  when  suddenly 
frightened  to  drop  food,  and  when  carrying  several  larvae 
in  the  beak  at  once,  the  one  nearest  the  end  of  the  beak 
would  be  the  one  most  likely  to  be  dropped  and  also  the  one 
least  liable  to  injury  by  the  beak.  Birds  sometimes  carry  in- 
sects, a  short  distance  without  any  apparent  purpose.  Mr. 
Bailey  saw  a  chickadee  take  seven  larvae  from  a  tree  and  fly 
away  with  them,  dropping  them  ten  feet  or  more  from  the 
tree.  Three  of  these  larvae  were  not  injured.  He  also  saw 
a  least  flycatcher  carry  away  three  female  moths,  only  one  of 
which  it  ate.  One  was  dropped  at  a  distance  of  twenty-five 
yards  from  the  tree  from  which  it  was  taken. 

There  is-  another  way  in  which  the  caterpillars  may  be  dis- 
tributed by  birds.  They  are  often  hatched  in  holes  of  trees 
and  in  bird  houses  frequented  by  birds,  especially  by  the 
English  sparrow.  When  first  hatched  in  such  places,  they 
are  likely  to  spin  down  on  their  threads,  and  bird  houses 


BIRDS  DISTRIBUTING  THE  MOTH.          237 

and  hollow  trees  have  been  found  in  which  these  spinning 
caterpillars  were  very  numerous.  The  caterpillars  may  be- 
come attached  to  the  feathers  of  birds  which  pass  to  and  fro, 
and  in  this  way  may  be  carried  short  distances.  Yet  the 
danger  of  distribution  by  the  accidental  dropping  of  cater- 
pillars by  birds  in  flight  does  not  appear  to  be  so  great  as 
that  resulting  from  the  dropping  of  caterpillars  at  the  nest. 
It  occasionally  happens  that  hairy  caterpillars  wriggle  out  of 
the  mouths  of  the  young  birds  and  are  dropped  into  or  below 
the  nests. 

Mr.  Bailey  saw  an  oriole  take  to  its  young  a  caterpillar  so 
large  that  the  latter  could  not  eat  it.  The  young  bird  placed 
its  foot  upon  the  caterpillar,  and  drawing  backward  ejected 
and  dropped  it  upon  the  ground.  The  old  birds  occasionally 
dropped  food  at  the  nest.  Mr.  Bailey  watched  a  pair  of 
chickadees  bringing  food  to  their  young.  They  appeared  to 
fly  about  half  a  mile  to  an  orchard  infested  with  the  canker- 
worm,  returning  to  the  nest  about  once  in  twelve  minutes 
with  food.  These  birds  dropped  a  few  of  the  canker-worms 
just  outside  the  nest.  A  new  colony  of  moths  was  discov- 
ered in  Cambridge  not  far  from  a  badly  infested  locality. 
The  appearance  of  the  colony  indicated  that  it  was  started 
by  crows,  as  the  larvae  were  scattered  all  about  in  the  vicinity 
of  the  crows'  nest.  If  several  caterpillars  of  the  same  species 
are  dropped  in  this  way,  there  is  a  strong  probability  of  a 
colony  being  formed  in  the  vicinity  of  the  nest.  A  bird  may 
overlook  a  few  caterpillars  near  its  nest,  preferring  to  go 
where  caterpillars  are  plentiful  rather  than  to  search  for  them 
where  they  are  scarce.  It  is  probable,  then,  that  the  bird 
which  is  most  useful  in  destroying  caterpillars  and  which 
feeds  the  largest  number  to  its  young  will  be  the  most  likely 
to  aid  in  the  distribution  of  the  moth.  The  danger  of  dis- 
tribution would  probably  be  greater  in  the  case  of  the  larger 
species  of  birds,  were  it  not  that  a  caterpillar  seized  in  the 
bill  of  a  crow  would  be  more  likely  to  be  seriously  injured 
than  one  taken  in  the  bill  of  a  small  bird.  The  danger  of 
distribution  to  distances  of  much  more  than  half  a  mile  by 
birds  in  this  way  does  not  seem  to  be  great. 

Mr.  Bailey  watched  a  catbird  taking  food  to  her  young. 
She  flew  back  and  forth  about  four  times  an  hour.  He 


238  THE   GYPSY  MOTH. 

could  see  her  go  and  come  for  at  least  a  thousand  yards. 
She  flew  about  twenty-five  yards  from  the  earth,  going 
straight  from  the  locality  in  which  her  nest  was  situated  to 
the  locality  from  which  she  procured  the  food.  Other  small 
birds  have  been  known  to  fly  an  equal  distance  to  secure 
food  for  their  young. 

The  distribution  of  caterpillars  by  birds  goes  to  prove  the 
rule  that  nature  does  not  usually  work  for  the  extermination 
of  species.  While  the  birds  are  very  useful  as  assistants  in 
the  work  of  extermination  by  destroying  the  gypsy  moths, 
they  hinder  the  work  to  some  extent  by  distributing  the 
larvae  and  the  female  moths. 

No  appreciable  distribution  of  caterpillars  by  birds  will 
occur,  however,  except  when  caterpillars  are  present  in  large 
numbers,  for  then  only  will  birds  go  to  a  distance  to  secure 
caterpillars  as  food  for  their  young.  Probably  no  other 
form  of  dissemination  of  caterpillars  by  birds  will  materially 
extend  the  moth's  distribution  even  under  the  most  favorable 
conditions.  Wherever  the  caterpillars  are  present  in  large 
numbers  in  a  settled  country,  they  will  be  carried  much  far- 
ther and  scattered  abroad  more  widely  by  man  and  domestic 
animals  than  by  birds.  In  woodlands  remote  from  civiliza- 
tion, birds  might  be  the  principal  factor  in  diffusing  the 
moth  to  a  short  distance  from  badly  infested  spots,  but  the 
distribution  of  the  moth  in  such  places  is  not  of  so  much 
moment  as  in  cultivated  and  settled  regions.  If  the  moth 
were  allowed  to  increase  and  spread  over  the  whole  State, 
we  may  infer  that  all  possible  distribution  by  birds  would 
be  of  little  importance  as  compared  with  the  good  they 
would  do  in  checking  the  increase  of  the  moth. 

In  towns  where  the  moths  are  few  and  where  most  of  them 
have  been  already  destroyed,  and  especially  in  small  isolated 
colonies,  birds  are  very  useful  allies  in  the  work  of  extermi- 
nation. In  such  localities  they  take  the  caterpillars  only 
when  they  come  in  their  way,  and  rarely  carry  them  to  their 
young  unless  the  nests  are  quite  near  the  infested  spot. 
Undoubtedly  in  many  such  cases  birds  have  contributed  as 
much  toward  the  extermination  of  the  nioth  as  have  the  men 
employed  in  the  work  of  extermination.  Where  the  cater- 
pillars are  few,  therefore,  birds  render  efficient  assistance  in 


BIRDS  DISTRIBUTING  THE  MOTH.          239 

the  work  of  extermination.  As  this  work  progresses,  birds 
become  more  and  more  useful  as  destroyers  of  the  moth  and 
less  dangerous  as  disseminators  of  the  insect. 

There  appears  to  be  little  if  any  danger  of  the  distribu- 
tion of  fertile  female  gypsy  moths  by  birds,  for,  though  birds 
have  frequently  been  seen  to  carry  the  female  moths  a  few 
feet  or  yards,  the  observations  of  five  years  have  not  afforded 
an  instance  of  their  carriage  to  a  greater  distance.  The  per- 
fect moths  are  to  be  found  only  in  midsummer  and  later,  a 
time  when  all  of  the  larger  and  most  of  the  smaller  birds 
have  no  young  in  the  nest. 

It  is  not  probable  that  the  birds  distribute  the  eggs  of  the 
moth  to  any  appreciable  extent,  though  they  undoubtedly 
scatter  them  somewhat  by  pecking  egg-clusters  from  the 
trees.  As  it  was  known  that  many  of  the  scattered  eggs 
hatch,  when  denuded  of  their  hairy  covering,  it  seemed  im- 
portant to  determine  whether  birds  would  break  the  egg 
shells  in  feeding  on  the  eggs,  and  whether  unbroken  eggs 
would  pass  through  the  digestive  tract  of  a  bird  without  in- 
jury to  the  shell  and  hatch  if  left  exposed  under  natural 
conditions.  Birds  might  thus  distribute  the  moth  as  widely 
as  they  are  known  to  distribute  certain  plants  by  scattering 
undigested  seeds.  A  confined  sparrow  was  fed  upon  the 
eggs  of  the  moth,  and  it  was  found  that  most  of  them  were 
broken  by  the  bird's  bill,  or  in  the  process  of  digestion ;  yet 
some  were  passed  entire.  A  similar  experiment  was  made 
with  the  crow.  As  the  crows  would  not  eat  the  eggs  of  the 
moth  unless  disguised  in  food  more  to  their  taste,  these 
eggs  were  inserted  in  the  bodies  of  grasshoppers  and  other 
large  insects,  and  while  thus  covered  were  swallowed  by  the 
crows.  A  small  proportion  of  these  eggs  were  passed  with 
the  shell  unbroken,  but  the  life  of  the  eggs  appears  to  have 
been  destroyed,  as  they  are  now  drying  up.  This  indicates 
that  there  is  no  danger  of  a  distribution  of  living  eggs  to  a 
distance  by  egg-eating  birds. 

Although,  as  has  been  shown,  certain  species  of  birds 
undoubtedly  assist  in  the  distribution  of  the  moth  by  carry- 
ing the  caterpillars  about,  birds  do  much  to  prevent  distribu- 
tion not  only  by  reducing  the  numbers  of  the  caterpillars, 
but  by  capturing  male  moths  in  search  of  isolated  females, 


240  THE   GYPSY  MOTH. 

thereby  preventing  the  fertilization  of  scattered  females  and 
the  establishment  of  new  colonies  of  the  moth.  Under  the 
most  favorable  circumstances  in  open  country  and  with  favor- 
ing wind  and  weather  the  male  will  occasionally  find  a  female 
at  a  distance  of  half  a  mile.  It  is  probable  that  in  orchards 
or  woodlands  the  scent  of  the  female  does  not  travel  so  far. 
In  any  case  a  male  flying  some  distance  to  a  female  would 
wander  about  a  good  deal  before  finding  its  mate.  In  the 
mean  time  it  must  run  the  gauntlet  of  the  flycatchers,  spar- 
rows, warblers  and  all  the  birds  which  so  frequently  capture 
flying  males.  It  is  to  these  birds  a  shining  mark,  and, 
although  its  flight  is  swift  and  eccentric,  they  readily  follow 
and  easily  capture  it.  When  flying  low  in  the  open  land 
male  moths  are  often  pursued  and  captured  by  sparrows. 
They  may  also  be  captured  by  swallows,  but  this  has  never 
been  observed.  Experiments  made  in  trapping  male  moths 
by  attracting  them  to  females  have  often  failed  because  of 
the  number  of  these  moths  captured  by  birds.  Birds  will 
sometimes  capture  every  male  moth  before  it  reaches  the 
trap.  Therefore  certain  species  do  much  in  this  way  to 
compensate  for  the  injury  which  they  or  others  may  do  in 
distributing  the  moth. 

Birds  versus   Useful  Insects. 

In  their  destruction  of  gypsy  moths  birds  sometimes 
destroy  parasites  of  these  insects.  The  parasites  within  the 
caterpillars  and  pupae  are  eaten  together  with  their  hosts. 
Yet  the  immediate  destruction  of  caterpillars  by  birds  is 
of  more  importance  to  man  than  the  lingering  death  which 
is  caused  by  the  parasite.  The  larvae  of  hymenopterous 
parasites  feed  almost  exclusively  on  the  fatty  portions  of  the 
insects  which  they  attack,  thus  allowing  them  to  live,  feed 
and  grow,  and  do  as  much  damage  to  vegetation  as  if  they 
were  not  parasitized.  When  the  caterpillar  has  finished 
feeding,  or  later  when  it  has  pupated,  the  parasite,  having 
eaten  the  greater  portion  of  the  fatty  substance,  eats  out 
the  vitals,  thus  killing  its  host.  The  bird,  on  the  contrary, 
snaps  up  the  caterpillar  at  once,  thus  preventing  further 
injury  to  the  tree.  The  question  then  arises,  would  the 
parasite  unhindered  be  more  effectual  in  checking  the  rav- 


BIRDS  VERSUS  INSECTS.  241 

ages  of  its  host  than  the  bird  ?  It  is  possible  that,  should 
predaceous  birds,  insects  and  other  enemies  be  insufficient 
in  holding  the  moth  in  check,  the  conditions  in  the  course 
of  years,  after  great  damage  had  been  done,  would  be  so 
favorable  for  the  multiplication  of  insect  parasites  that  they 
might  check  for  a  time  the  ravages  of  the  moth.  Experience 
in  many  countries  shows  that,  where  other  enemies  of  a 
pest  fail  to  hold  it  in  check,  insect  parasites,  starvation  and 
epidemic  diseases  sometimes  put  an  end  for  the  time  being 
to  the  plague.  In  addition  to  the  destruction  of  parasites, 
together  with  the  host,  some  ichneumons  and  tachinid 
flies  are  captured  in  the  imago  form  by  the  flycatchers. 
Birds  also  destroy  some  of  the  predaceous  insects.  This 
is  especially  true  of  robins,  jays  and  crows.  Yet  Pro- 
fessor Forbes  has  shown  that  the  destruction  of  such  insects 
by  birds  is  not  necessarily  an  evil.*  The  bugs  which  appear 
to  be  most  useful  in  the  destruction  of  the  moth  are  believed 
to  have  some  immunity  from  the  attacks  of  birds  by  reason 
of  their  pungent  secretions.  Crows,  however,  destroy  cer- 
tain of  these  bugs. 

Conclusions. 

Our  present  knowledge  of  birds  as  enemies  of  the  gypsy 
moth  in  Massachusetts  points  to  the  following  conclusions  :  — 

At  least  a  dozen  species  are  very  useful  in  this  respect  ; 
probably  twenty-five  others  are  more  or  less  useful,  when 
the  moths  become  very  numerous,  or  when  other  species  of 
insects  which  these  birds  prefer  are  scarce.  -f 

Birds  destroy  larger  numbers  of  the  gypsy  caterpillars 
when  the  canker-worms  or  other  hairless  larvae  are  scarce 
than  when  they  are  plentiful. 

Although  birds  gather  in  localities  infested  by  the  moth 
for  the  purpose  of  feeding  on  the  caterpillars,  they  do  not 
flock  to  such  infested  localities  in  such  numbers  as  they  do 
to  regions  infested  by  migrating  locusts  or  by  hairless  cater- 
pillars. 

Birds  are  particularly  useful  in  preventing  the  increase  of 
small  colonies  of  the  moth,  and  in  this  respect  are  allies  to 


*  Bulletin  No.  3,  Illinois  State  Laboratory  Natural  History,  November,  1880, 
page  83. 


242  THE   GYPSY  MOTH. 

man  in  the  work  of  extermination.  A  few  cases  are  noted 
in  which  such  colonies  appear  to  have  been  exterminated  by 
birds.  They  are  also  useful' in  checking  the  increase  of  the 
moth  in  large  colonies. 

More  species  of  birds  are  found  attacking  the  moth  in 
orchards  than  in  woodlands,  though  woodland  birds  often 
visit  orchards  situated  near  their  usual  haunts,  and  orchard 
birds  visit  badly  infested  colonies  in  woodlands. 

While  birds  are  very  useful  in  restraining  local  ravages  of 
the  moth,  it  is  probable  that  should  the  moth  be  allowed  to 
spread  over  the  whole  State,  its  increase  would  so  outrun  the 
numbers  of  birds  that  they  would  have  no  appreciable  efiect 
in  checking  its  most  serious  outbreaks. 

The  injury  done  by  birds  in  distributing  the  moth  and 
destroying  parasites  and  other  useful  insects  appears  to  be 
of  little  importance  when  compared  with  the  good  they  do 
in  destroying  the  moth. 

If  laws  for  the  protection  of  birds  were  enforced,  and  if 
birds  were  fostered,  encouraged  and  protected  generally  by 
citizens,  there  is  no  doubt  that  their  efficiency  as  insect  de- 
stroyers could  be  greatly  increased.  The  most  important 
service  that  could  be  rendered  by  birds  in  the  case  of  the 
gypsy  moth  would  be  the  destruction  of  the  eggs.  This 
service,  supplemented  by  that  of  destroying  the  other  forms 
of  the  moth  in  summer,  would  be  of  very  material  benefit. 
As  no  American  birds  appear  to  eat  the  eggs  to  any  extent, 
it  would  be  well  to  investigate  thoroughly  the  habits  of 
European  egg-eating  species,  with  a  view  to  their  introduc- 
tion into  Massachusetts,  if  this  should  be  found  desirable.  ' 

The  Protection  of  Birds. 

It  is  quite  evident  that  by  pursuing  a  policy  for  the  pro- 
tection of  birds,  the  number  of  birds  in  the  region  infested 
by  the  gypsy  moth  and  their  efficiency  as  insect  police  could 
be  greatly  increased.  While  the  present  laws  for  the  pro- 
tection of  insectivorous  birds  are  wise  in  the  main,  no 
adequate  provision  is  made  for  their  enforcement,  and  they 
are  consequently  a  dead  letter  to  certain  classes  of  people. 
A  great  many  birds  are  killed  and  many  nests  broken  up 
by  boys.  In  the  fall  the  country  swarms  with  gunners. 


PROTECTION  OF  BIRDS.  243 

Thousands  of  birds  are  killed  for  the  milliners.  The  camps 
of  Italians,  where  employees  engaged  in  public  works  are 
quartered,  furnish  many  of  these  gunners.  These  men  will 
shoot  birds  of  any  kind,  anywhere  and  on  any  man's  premises. 
Everything  that  wears  feathers  is  considered  by  them  as  fair 
game. 

The  appointment  of  officers  to  enforce  the  bird  laws  might 
assist  much  in  bird  protection.  Children  in  the  public  schools 
should  be  taught  the  usefulness  of  birds,  and  it  should  be 
generally  considered  a  crime  to  destroy  insect-eating  birds. 
The  farmer  might  as  well  allow  men  to  steal  his  fruit  and 
grain  as  to  shoot  the  insect-eating  birds  on  his  premises. 
The  number  of  birds  destroyed  by  cats  is  astonishing.  I 
have  known  a  single  cat  to  break  up  the  nests  of  six  pairs  of 
birds  in  a  day,  destroying  all  the  young  and  one  of  the  old 
birds.  Many  wild  and  vagabond  cats  roam  the  woods  and 
orchards  and  destroy  thousands  of  birds.  Outside  the  cities 
cats  probably  do  enough  injury  by  killing  birds  to  much 
more  than  counterbalance  all  the  benefit  derived  from  them 
in  the  way  of  destroying  rats  and  mice.  A  few  traps  prop- 
erly attended  by  a  bright  boy  will  do  more  towards  clearing 
a  place  of  rats  and  mice  than  half  a  dozen  average  cats. 

The  number  of  such  birds  as  nest  in  boxes  or  hollow  trees 
can  be  increased  by  putting  up  boxes  in  which  they  may 
breed,  and  protecting  them  as  far  as  possible  from  the  English 
sparrow  and  other  enemies.  If  evergreen  hedges  and  patches 
of  shrubbery  are  provided  as  retreats  for  birds  to  which  they 
can  fly  when  pursued  by  hawks,  and  if  plenty  of  wild  and 
cultivated  fruit  is  grown  in  the  vicinity,  such  a  locality  will 
be  much  frequented  by  birds. 

Birds  may  be  attracted  to  infested  localities  in  the  winter 
or  summer  by  supplying  them  with  food  and  safe  nesting- 
places.  A  people  who  protect  and  foster  insectivorous  birds 
oannot  fail  to  add  materially  to  the  prosperity  of  agriculture. 


244  THE   GYPSY  MOTH. 


THE  PROGRESS   OF  EXTERMINATION. 

The  extermination  of  the  gypsy  moth  was  begun  by  the 
Commonwealth  under  a  misapprehension  of  the  facts.  When 
the  first  great  outbreak  of  the  pest  was  brought  to  the  atten- 
tion of  the  Legislature  in  1890,  it  was  believed  that  the  moth 
was  confined  to  cultivated  lands  in  the  town  of  Medford. 
This  infested  district  was  not  supposed  to  exceed  one-half 
mile  in  width  and  one  and  one-half  miles  in  length.  The 
difficulty  and  expense  of  extermination  were  consequently 
underestimated.  An  appropriation  was  made  for  the  pur- 
pose of  exterminating  the  moth  in  this  small  tract  and 
preventing  its  spread  to  other  parts  of  the  State.  In  the 
attempt  to  exterminate  the  moth,  the  experience  of  the  first 
year  showed  that  the  insect  was  not  confined  to  Medford,  and 
the  commission  of  1890  reported  that  fifty  square  miles  were 
more  or  less  infested.  The  experience  of  the  second  year 
proved  that  the  moth  was  distributed  over  an  area  of  over 
two  hundred  square  miles,  not  only  in  cultivated  lands  but 
in  waste  and  wood  lands  as  well.  The  magnitude  of  the  task 
undertaken  by  the  Commonwealth  then  became  apparent. 

Circumstances  favoring  Extermination. 

There  are  certain  circumstances  connected  with  the  habitat 
of  the  moth,  which,  taken  together  with  known  facts  in  its 
life  history,  encourage  the  attempt  to  secure  its  extermina- 
tion. 

Limited  Area  Occupied.  —  The  experience  of  five  years 
confirms  the  belief  that  the  moth  is  confined  to  a  limited  area 
on  and  near  the  coast  line. 

Favorable  Location.  —  The  infested  region  is  bounded  on 
the  east  and  south-east  by  the  ocean,  which  prevents  the 
spread  of  the  moth  in  those  directions.  -  Much  of  the  territory 
along  the  coast  consists  of  salt  marsh,  in  which  the  gypsy 
moth  cannot  live. 

The  infested  region  is  in  the  most  populous  portion  of 


EXTERMINATION.  245 

the  State ;  therefore  the  extermination  of  the  moth  directly 
interests  a  large  number  of  people.  This  fact  assures  the 
intelligent  co-operation  of  many  individuals. 

The  original  centre  of  infestation  in  the  district  was  situated 
on  a  short  line  of  railroad  ending  in  Boston,  and  thus  the 
danger  of  distribution  by  rail  was  not  great. 

The  Infested  Area  has  been  reduced.  —  As  a  result  of  the 
work  of  extermination,  the  region  now  occupied  by  the  gypsy 
moth  is  considerably  less  than  that  occupied  by  it  five  years 
ago,  when  the  work  was  begun. 

Slow  Spreading.  —  The  female  moth  does  not  fly.  On 
this  fact  rests  the  principal  hope  of  preventing  the  spread  of 
the  insect,  and  finally  securing  its  extermination.  Could 
the  female  moth  fly,  as  does  the  male,  the  species  would 
probably  have  been  distributed  long  since  over  all  eastern 
Massachusetts  and  adjacent  parts  of  New  England,  if  not 
farther.  The  moth  occupied  twenty  years  from  the  time  of 
its  introduction  in  spreading  over  the  territory  infested  by 
it  in  1891. 

The  Moth  hibernates  in  the  Egg.  —  It  remains  in  that 
form  during  most  of  the  fall,  the  winter  and  early  spring. 
The  eggs  are  conspicuous,  and  an  opportunity  is  thus  given 
for  inspecting  the  territory  and  discovering  the  colonies  of 
the  moth  during  the  fall  and  winter  months,  while  the  trees 
are  leafless  and  the  insect  is  doing  no  damage.  It  is  more 
feasible  to  exterminate  an  insect  pest  which  may  be  attacked 
in  the  winter,  when  it  is  stationary  for  a  fixed  period,  than 
to  exterminate  a  species  that  can  be  reached  only  during 
the  summer  months,  at  which  time  its  distribution  is  being 
effected. 

Obstacles  to  Extermination. 

Though  there  are  many  encouraging  circumstances  in 
connection  with  the  problem,  there  are  also  serious  obstacles 
to  success. 

Enormous  Reproductive  Capacity  of  the  Moth.  —  Its  won- 
derful reproductive  powers  and  its  remarkable  tenacity  of 
life  provide  for  a  rapid  increase  and  redistribution  in  an  in- 
fested locality  in  the  inspection  of  which  a  few  moths  may 
have  been  overlooked. 


246  THE  GYPSY  MOTH. 

Many  Food  Plants.  —  Where  the  moth  is  abundant,  it  is 
found  on  nearly  all  plants  of  economic  value.  In  inspecting 
a  region  in  search  of  the  moth  it  is  necessary  to  examine  all 
species  of  trees.  It  is  therefore  much  more  difficult  and 
expensive  to  locate  all  the  colonies  than  it  would  be  were 
the  insects  confined  to  a  few  food  plants. 

Other  Obstacles.  — The  infested  region  being  densely  pop- 
ulated, the  danger  of  local  distribution  and  reinfestation  by 
man  and  animals  constantly  passing  and  repassing  infested 
centres  is  much  greater  than  it  would  be  were  the  district 
thinly  populated. 

No  one  method  can  be  depended  upon  for  exterminating 
the  moth.  Nature  often  defeats  an  attempt  to  exterminate 
by  a  single  process  at  a  particular  season  of  the  year. 
The  most  approved  methods  applied  singly  frequently  fail. 
Exterminative  work  must  proceed  day  after  day  throughout 
the  year,  to  insure  success.  Though  every  effort  was  made 
in  1891  to  exterminate  the  moth  from  the  region  most  in- 
fested, the  inspection  of  1892  gave  abundant  evidence  of  the 
impossibility  of  extermination  in  one  year's  time.  In  1891 
the  destruction  of  the  eggs  was  depended  upon  for  extermi- 
nation. Yet  caterpillars  were  found  in  1892,  even  in  those 
parts  of  the  infested  territory  where  the  work  had  been  most 
carefully  done,  and  where  the  greater  part  of  the  eggs  had 
been  destroyed.  Many  of  these  came  from  eggs  which  had 
been  scattered  on  the  ground  in  the  previous  fall  and  winter 
before  the  work  of  destroying  the  clusters  was  begun.  Eggs 
are  sometimes  thus  scattered  by  the  wind  and  rain,  by 
people  picking  fruit  or  pruning  or  cutting  trees,  by  birds 
and  animals,  or  by  various  other  causes.  The  female  moth 
occasionally  drops  a  few  eggs  upon  the  ground  or  in  crevices 
of  the  bark,  where  they  will  escape  the  most  thorough 
search.  Spraying,  as  ordinarily  done,  will  destroy  only  a 
small  portion  of  the  caterpillars.  Bands  of  insect  lime  and 
other  tree  protectors  merely  prevent  most  of  the  caterpillars 
from  ascending  trees  which  have  been  first  cleared  of  eggs. 
If  thus  kept  out  of  trees,  they  will  betake  themselves  to 
other  plants.  While  the  burlap  bands  afford  a  means  of 
disposing  of  most  of  the  caterpillars,  there  can  be  no  cer- 
tainty of  taking  them  all  by  this  method. 


PLATE   XXXVI.      Men   at   work   on   the   Dexter   elm,   Maiden.      From 
photograph. 


EXTERMINATION.  247 

The  Success  of  Local  Extermination. 
The  work  of  extermination  was  begun  on  the  principle 
that,  if  the  moths  could  be  exterminated  from  one  tree,  they 
could  be  eradicated  from  any  number  of  trees,  providing  the 
same  kind  of  work  that  cleared  the  first  tree  could  be  carried 
on  simultaneously  over  a  large  area.  It  was  soon  found  that 
the  moth  could  be  cleared  from  trees  of  ordinary  size  by 
honest,  thorough,  intelligent  labor.  Yet  many  doubters 
asserted  that  it  was  impossible  to  clear  the  larger  trees. 
Medford,  being  one  of  the  oldest  towns  in  the  State,  had 
many  very  large  elms.  This  was  also  true  of  Maiden.  It 
was  believed  by  some  of  the  residents  that  it  would  be  im- 
possible to  clear  the  moths  from  these  trees  except  by  the 
aid  of  a  balloon.  The  largest  tree  in  the  infested  region  was 
selected  for  trial  of  the  possibility  of  extermination.  This 
tree  is  situated  on  the  property  of  the  Messrs.  Dexter  of 
Maiden,  and  stands  in  front  of  the  old  Dexter  mansion. 
The  tree  has  been  owned  by  this  family  for  more  than  two 
hundred  years.  If  not  the  largest  tree  in  the  State,  it  is 
one  of  the  largest.*  Early  in  1891  an  attempt  was  made 
to  clear  the  moths  from  the  tree,  and  a  gang  of  four  men, 
who  had  had  some  experience,  went  to  work  upon  it  to 
destroy  the  eggs  of  the  moth.  After  working  for  several 
days  upon  the  tree  they  reported  it  cleared.  Another  gang 
of  men  was  put  at  work  upon  the  tree,  and  six  hundred 
additional  egg-clusters  were  discovered.  Notwithstanding 
this,  caterpillars  appeared  in  the  spring  upon  the  tree.  It 
was  then  sprayed  thoroughly,  an  extension  ladder  sixty-five 
feet  in  length  being  used,  together  with  several  additional 
ladders  placed  in  various  parts  of  the  tree.  Later  in  the 
season  all  the  holes  in  the  limbs  were  covered  or  filled,  and 
the  few  egg-clusters  found  were  treated  with  creosote  oil. 
In  1892  the  tree  was  banded  with  tarred  paper,  which  was 
kept  constantly  moist  with  a  mixture  of  tree  ink,  tar  and 
oil.  A  few  caterpillars  were  found,  however,  on  the  tree, 
having  hatched  probably  from  scattered  eggs  left  in  the 

*  The  Dexter  elm  has  the  following  dimensions  :  circumference  at  base,  29  feet ; 
circumference  six  feet  from  ground,  21  feet ;  height,  110  feet ;  spread  from  north- 
east to  south-west,  104  feet.  Some  of  the  branches  of  the  tree  are  3  feet  in 
diameter. 


248  THE   GYPSY  MOTH. 

crevices  of  the  bark.  In  1893  no  caterpillars  appeared, 
and  no  form  of  the  moth  has  been  found  since  1892  upon  the 
tree.  In  the  inspections  of  the  tree  every  care  has  been 
taken  to  go  over  it  thoroughly,  from  its  highest  branches  to 
the  base  of  the  trunk.  The  dead  limbs  have  been  removed 
and  holes  have  been  covered,  but  no  other  work  has  been 
necessary  at  the  regular  inspections.  Plate  XXXVI.  shows 
men  at  work  in  the  inspection  of  the  tree. 

The  extermination  of  the  moth  from  many  orchards  was 
accomplished  without  much  difficulty .  Plate  XXXVH.  shows 
apple  trees  which  were  seriously  injured  during  the  season 
of  1891  by  the  gypsy  moth.  They  were  cleared  of  the  moths 
and  so  treated  that  in  1892  they  regained  a  large  part  of 
their  foliage  (Plate  XXXVHI . ) .  They  have  borne  very  little 
fruit,  however,  since  1891. 

Having  learned  that  it  was  possible  to  clear  the  moth 
from  any  tree,  it  remained  to  be  proved  whether  the  creat- 
ure could  be  cleared  from  orchards  or  entire  estates. 
Although  in  1891  many  estates  appeared  to  have  been 
cleared,  there  was  still  some  doubt  that  the  moths  were 
exterminated  from  them.  But  the  estates  were  examined 
again  and  again  in  succeeding  years,  and  no  moths  were 
found  except  in  a  very  few  instances.  The  number  of 
infested  estates  from  which  the  moths  had  been  cleared 
increased  annually.  Not  only  were  estates  cleared,  but 
infested  localities  consisting  of  many  estates  were  entirely 
freed  from  the  moth. 

More  than  a  thousand  colonies  in  the  infested  region,  some 
of  them  covering  many  estates,  have  been  entirely  cleared 
of  the  moth  and  have  remained  clear,  until  it  has  become  an 
established  fact  that  wherever  the  moths  are  found  in  open 
and  cultivated  lands,  they  can  be  exterminated.  The  diffi- 
culty of  exterminating  the  moth  in  woodland  has  been  found 
to  be  much  greater.  Yet,  despite  all  obstacles,  some  of 
which  at  first  seemed  insurmountable,  the  moths  have  been 
cleared  from  certain  infested  localities  in  the  woods.  The 
destruction  of  all  vegetation  by  fire  will  accomplish  exter- 
mination in  woodlands.  But  much  of  this  infested  woodland 
is  retained  by  the  Commonwealth  for  park  purposes,  and  the 
destruction  of  the  trees  is  out  of  the  question,  however  much 


PLATE  XXXVII.     Apple  trees  stripped  by  caterpillars  of  the  gypsy  moth, 
Swampscott.    From  a  photograph  taken  Aug.  5,  1891. 


PLATE  XXXVIII.     View  of  the  same  trees  in  Swampscott  a  year  later, 

after  the  moths  had  been  cleared  from  the  locality  by  the  agents 

of  the  Board  of  Agriculture.    From  a  photograph 

taken  in  July,  1892. 


EXTERMINATION.  249 

the  exigencies  of  the  case  might  seem  to  warrant  such  a  course. 
Therefore  burlapping,  banding,  spraying  and  other  means, 
less  expeditious  and  in  the  end  more  expensive  than  fire, 
have  been  resorted  to.  These  means  call  for  larger  appro- 
priations than  have  yet  been  made,  and  without  such  appro- 
priations, promptly  granted,  the  extermination  of  the  moth 
can  never  be  accomplished.  Though  a  continual  advance  in 
the  work  of  extermination  has  been  made  annually  in  the  outer 
towns  of  the  infested  district,  though  some  of  them  appear 
quite  and  others  nearly  cleared  of  the  moth,  there  is  a  section 
of  woodland  in  the  inner  towns  which  is  probably  in  a  worse 
condition  than  it  was  in  in  1891. 

Larger  Appropriations  Needed. 

While  the  agents  of  the  Board  have  been  engaged  in  pre- 
venting the  spreading  of  the  moth  and  prosecuting  the  work 
of  extermination  in  the  outer  towns  of  the  infested  region, 
they  have  been  unable  to  do  much  more  with  the  means  pro- 
vided than  to  check  the  moth's  annual  increase  in  the  central 
towns.  This  partial  policy,  the  inevitable  consequence  of 
the  inadequate  appropriations,  has  necessitated  in  the  inner 
towns  an  annual  repetition  of  the  work  and  expense  with- 
out any  considerable  advance  towards  extermination  in  those 
towns.  As  a  result,  while  extermination  has  been  success- 
ful over  large  areas,  principally  in  the  outer  towns,  the 
moths  have  increased  in  the  comparatively  neglected  wood- 
land in  the  central  towns.  The  Board  is  required  by  law 
to  do  all  possible  toward  preventing  the  spread  and  securing 
the  extermination  of  the  gypsy  moth  in  this  Commonwealth. 
All  possible  with  the  means  at  hand  has  been  undertaken. 
All  the  evidence  obtainable  goes  to  show  that  the  spread  of 
the  moth  into  territory  outside  the  region  infested  in  1891 
has  been  prevented,  and  that  extermination  has  been  accom- 
plished both  locally  and  over  a  considerable  area,  greatly 
reducing  the  infested  territory.  Our  only  hope  of  prevent- 
ing the  spreading  of  the  moth  lies  in  doing  everything  possible 
to  exterminate  it.  Therefore,  whatever  imperils  the  success 
of  extermination,  renders  the  prevention  of  the  moth's  dis- 
semination less  certain.  The  expense  of  extermination  has 
been  greatly  augmented  and  success  retarded  and  gravely 


250  THE   GYPSY  MOTH. 

imperilled  by  inadequate  resources  and  repeated  delays  in 
making  the  annual  appropriations.  Unless  ample  appropri- 
ations are  promptly  granted,  failure  is  certain. 

To  continue  the  past  policy  of  inadequate  and  belated  ap- 
propriations may  result  sooner  or  later  in  the  escape  of  the 
moth  from  the  territory  to  which  it  is  at  present  confined  and 
its  final  distribution  over  the  whole  country.  In  such  a  case 
it  might  injure  the  agricultural  interests  beyond  calculation. 
If  the  gypsy  moth  should  be  allowed  to  spread  over  the 
United  States,  the  average  farmer  would  be  powerless,  under 
the  conditions  prevailing  in  this  country,  to  protect  his  or- 
chard, woodland  or  garden  against  the  ravages  of  this  insect. 
Whatever  affects  the  prosperity  of  the  farmer  affects  the 
prosperity  of  the  whole  people.  Knowing  as  we  do  that  the 
moth  feeds  on  nearly  all  forest  and  orchard  trees  and  garden 
plants,  knowing  also  the  injury  done  in  Europe  within  the 
past  century  by  this  insect,  having-  learned  by  experience  the 
greatly  increased  destructiveness  of  European  insects  when 
introduced  here,  and  considering  the  annual  damage  now  done 
to  agriculture  by  insects  in  this  country  (estimated  by  an  em- 
inent authority  at  three  hundred  and  eighty  million  dollars) , 
we  can  but  view  with  alarm  the  possibility  of  the  spread  of 
this  insect  over  the  United  States. 

There  is  no  doubt  in  the  minds  of  those  acquainted  with 
the  facts  that  the  gypsy  moth  can  be  held  in  check  where  it 
now  is  and  that  it  can  be  exterminated  if  sufficient  resources 
can  be  secured  and  vigorous  measures  taken.  It  would  seem, 
then,  that  the  general  government  should  seize  the  opportunity 
now  presented  to  stamp  out  the  pest  which  Massachusetts 
undertook  to  exterminate  as  soon  as  it  was  publicly  known 
that  it  was  within  her  borders,  reducing  its  numbers  and  the 
area  of  its  dissemination  by  local  extermination  and  thus  far 
holding  it  in  check.  The  policy  of  control  or  extermination 
of  insect  pests  by  governmental  commissions,  which  has  been 
so  successful  in  certain  European  countries,  might  be  applied 
to  advantage  in  this  case  by  the  government  of  the  United 
States.  There  are  those  who  believe  that  neither  the  State 
nor  nation  should  appropriate  money  for  the  extermination 
of  this  insect,  but  that  land  owners  should  be  left  to  protect 
their  own  property  from  its  ravages.  According  to  Professor 


EXTEBMINATION.  251 

Fernald,  this  would  prove  to  be  the  worst  possible  policy, 
as  after  the  moths  had  spread  over  the  State,  the  expense  to 
land  owners  would  be  enormous  as  compared  with  the  expense 
of  the  work  as  carried  on  by  the  State  in  the  present  re- 
stricted territory.  He  makes  the  following  comparison  in 
his  report  on  the  work  of  1895,  made  to  the  gypsy  moth 
committee  of  the  State  Board  of  Agriculture  :  — 

' '  The  value  of  the  taxable  property  in  this  State  is 
$2,429,832,966,  and  an  appropriation  of  $200,000  is  a  tax 
of  less  than  one-twelfth  of  a  mill  on  a  dollar.  A  man  having 
taxable  property  to  the  amount  of  $5,000  would  have  to  pay 
a  tax  of  only  41  cents  and  6  mills.  This  beggarly  sum  of 
money  would  make  but  a  small  show  in  the  work  of  clearing 
the  gypsy  moth  caterpillars  from  an  infested  $5,000  farm, 
while  in  the  uninfested  parts  of  the  State  the  land  owners 
would  be  paying  an  exceedingly  small  premium  to  the  State 
to  insure  them  against  the  ravages  of  the  gypsy  moth.  This 
premium  on  a  $1,000  farm  would  be  8£  cents,  and  for  fifty 
years  it  would  amount  to  only  $4.16f.  This  protection 
would  extend  not  only  to  farmers  and  owners  of  forest  lands, 
but  also  to  residents  in  villages  and  cities  who  own  lands 
with  trees  and  shrubs  on  them,  and  to  vegetation  wherever 
grown  within  the  limits  of  our  Commonwealth." 

The  expense  of  this  work,  if  undertaken  by  the  United 
States  government,  would  be  infinitesimal  to  the  individual 
citizen  and  would  be  an  economical  insurance  against  the 
ravages  of  the  moth  on  his  property  and  that  of  his  posterity. 


THE    G-YPSY    MOTH 

PORTHETRLA    DISPAR     (L.)  . 


II. 


C.     H.     IF1  DE  tt  1ST  .A.  L  3D  . 


PLATE  39. 


EXPLANATION  OF  PLATE  39. 


Drawn  in  colors  by  ELLA  M.  PALMER. 


It  has  seemed  desirable  to  present  colored  figures  of  the  following  insects  since 
in  some  of  their  forms  they  are  the  ones  most  commonly  mistaken  for  the  gypsy 
moth. 

1.  Eggs  of  Euvanessa  antiopa  (Linn.)    (Vanessa 

butterfly) . 

2.  Caterpillar  of  E&ivanessa  antiopa. 

3.  Chrysalis      "  "  " 

4.  Imago  " 

5.  Egg-cluster  of    Clisiocampa    americana    Harr. 

(tent  caterpillar). 

6.  Caterpillar  of  Clisiocampa  americana. 

7.  Cocoon         "  "  " 

8.  Male  imago  of          "  " 

9.  Female  imago  of     "  " 

10.  Caterpillar    of  Orgyia    antiqua    (Linn.). 

11.  Male  imago  "         "  " 

1 2 .  Egg-cluster  of  Orgyia  definita  Pack. 

13.  Caterpillar     "        "  " 

14.  Male  imago  "        "  " 

15.  Egg-cluster  of  Orgyia  leucostigma  (S.  and  A.) 

(the  white  marked  tussock  moth). 

1 6.  Caterpillar    of    Orgyia    leucostigma. 

17.  Male  imago  of       "  " 

1 8.  Female  imago  of    "  *' 


THE   GYPSY  MOTH. 


Porthetria  dispar  (X.)« 


This  species  was  first  described  by  Linnaeus,  in  1758,  in 
the  tenth  edition  of  his  "  Systema  Naturae,"  Vol.  I,  page  501, 
under  the  name  of  Phalcena  (Boinbyx)  dispar,  the  specific 
name  being  given  because  of  the  marked  difference  or  dis- 
parity between  the  sexes.  In  1801,  Schrank,  in  his  "Fauna 
Boica,"  placed  this  species  under  his  genus  Laria;  but  this 
generic  name  had  been  previously  used  by  Scopoli  in  the 
beetles,  and  thus,  being  preoccupied,  could  not  properly  be 
used  for  the  moths.  In  1810,  Ochsenheimer,  in  the  third 
volume  of  his  "  Schmetterlinge  von  Europa,"  established  the 
genus  Liparis  and  put  dispar  under  it ;  but  Liparis  is  also 
preoccupied,  and  cannot  be  used.  Hiibner,  in  his  "Ver- 
zeichniss  bekannter  Schmetterlinge,"  page  160,  published 
about  1822,  placed  dispar  in  his  genus  Porthetria  with  three 
exotic  species,  and  therefore  dispar,  being  the  only  European 
species,  has  been  taken  as  the  type.  In  the  same  work,  page 
158,  Hiibner  established  the  genus  Ocneria  with  rubea  Fab. 
as  the  type,  but  Staudinger  and  some  others,  believing  that 
rubea  and  dispar  should  be  in  the  same  genus,  placed  them 
with  their  allies  under  Ocneria. 

In  1829,  Stephens,  in  his  "Illustrations  of  British  Ento- 
mology," Haustellata,  Vol.  II,  page  55,  established  the  genus 
Hypogymna  and  placed  dispar  under  it.  He  also  proposed 
this  name  in  his  catalogue  the  same  year.  In  accordance 
with  the  laws  of  priority,  almost  universally  accepted  by 
zoologists,  it  is  necessary  to  adopt  the  oldest  tenable  generic 
name  which  is  not  preoccupied ;  and  therefore  Hiibner's  genus 
Porthetria,  with  dispar  as  the  type,  was  given  by  Kirby  in 
his  recent  "Catalogue  of  Lepidoptera  Heterocera,"  and  has 
been  adopted  by  Comstock  and  Dyar  in  this  country. 


256  THE  GYPSY  MOTH. 

The  question  whether  dispar  shall  remain  under  the  genus 
Ocneria  depends  on  whether  it  has  the  same  generic  charac- 
ters as  rubea.  If  it  has,  then  it  should  remain  with  rubea, 
otherwise  it  should  be  placed  under  the  genus  Porthetria. 
To  settle  this  question  to  my  own  satisfaction,  I  sent  to 
Europe  and  obtained  specimens  of  Ocneria  rubea,  and,  after 
a  critical  study  of  the  structure,  I  am  convinced  that  the  two 
insects  are  not  congeneric,  and  must  be  placed  under  differ- 
ent genera.  On  showing  the  insects  to  Prof.  J.  B.  Smith, 
he  agreed  with  me  in  my  conclusions,  and  in  a  letter  from 
Prof.  A.  R.  Grote  of  Bremen,  Germany,  I  learned  that  he 
had  independently  reached  the  same  conclusion.  I  therefore 
feel  obliged  to  adopt  the  name  Porthetria  dispar,  given  by 
Hiibner  over  seventy  years  ago.  In  all  our  previous  pub- 
lications, however,  the  name  Ocneria  dispar  has  been  used, 
following  Staudinger's  catalogue. 

COMMON  NAMES. 

The  following  are  some  of  the  common  names  which  have 
been  given  to  this  insect  in  different  European  countries.  We 
have  adopted  the  common  name  "gypsy  moth,"  because  it  is 
the  one  most  frequently  used  in  England,  and  has  already 
come  into  very  general  use  in  this  country.  This  name  was 
first  given  to  it,  so  far  as  I  can  learn,  by  Wilkes,  in  1741 ; 
and  Humphreys,  in  his  "British  Moths,"  says  that  "the 
popular  name  of  the  gypsy  was  no  doubt  suggested  by  the 
brown,  tanned  kind  of  color  of  the  male." 

SCHWAMMSPINNER  :  Fungus-spinner.     The  egg-cluster  resembles  a 

small  tree  fungus. 
DiCKKOpr :  Thick-head.    The  head  of  the  caterpillar  is  unusually 

large. 

ROSENSPINNER  :  Rose-spinner.     They  feed  on  rose  bushes. 
APRICOSENSPINNER  :  Apricot-spinner. 
STAMMPHALJENE  :  Stem-moth.    The  moths  rest  on  the  trunks  of 

trees. 

GROSSKOPF  :  Great-head. 
BAUMRAUPE  :  Tree-caterpillar. 
SCHWAMMRAUPE  :  Fungus-caterpillar. 
GROSSE  SCHWAMMRAUPE  :  Great  fungus-caterpillar. 
SCHWAMMMOTTE  :  Fungus-moth. 
STAMMRAUPE  :  Stem-caterpillar. 
GROSSKOPFSPINNER  :  Great-head  spinner. 


COMMON  NAMES  AND   BIBLIOGRAPHY.     257 

UNGLEICHER  SPINNER:  Dissimilar  spinner.      The  sexes  are  very 

unlike. 

UNGLEICH  NACHFALTER  :  Dissimilar  nocturnal-moth. 
ZWEIFACH:  Two-fold. 
GROSSKOPFBAR  :  Great-head  bear. 
DICKKOPFIGER  BAR  :  Thick-headed  bear. 
LE  BOMBYX  DISSEMBLABLE  :  The  dissimilar  bombyx. 
LE  BOMBYX  DISPARATE  :  The  dissimilar  bombyx. 
LA  SPONGIEUSE:  The  spongy  (moth). 
LA  CHENILLE  COMMUNE  :  The  common  caterpillar. 
LE  ZIG-ZAG. 
THE  GYPSY  MOTH. 
THE  BROWN  ARCHES. 


LITERATURE  ON  THE  GYPSY  MOTH. 

All  the  works  in  this  list  have  been  examined  except  those 
marked  with  an  asterisk. 


Goedart,  Histoire  des  Insectes,  vol.  I,  pp.  118,  142,  pi.  63,  1662. 

Merian,  Erucarum  Ortus,  etc.,  part  I,  pi.  18-31,  1679. 

Merian,  Erucarum  Ortus,  etc.,  part  II,  pi.  19,  1683. 
*Blankaart,  Schauplatz  der  Raupen,  p.  25,  pi.  6,  figs.  A-C,  1690. 

Frisch,  Beschreib.  von  Ins.,  vol.  I,  p".  14,  pi.  3,  figs.  1-9,  1720. 

Frisch,  Beschreib.  von  Ins.,  suppl.,  vol.  XIII,  p.  28,  1722. 

Merian,  Erucarum  Ortus,  folio  edition,  pi.  183,  1730. 

La  chenille  &  oreilles,  Reaumur,  Memoires,  vol.  I,  p.  110,  pi.  3,  figs.  1, 
3-5;  p.  19,  pi.  4,  figs.  1-4,  6-8;  p.  352,  pi.  22,  figs.  5,  6,  8-10;  p. 
859,  pi.  24,  figs.  1-4 ;  p.  609,  pi.  45,  figs.  1-13 ;  p.  614,  pi.  46,  figs.  1-7, 
1734. 

La  chenille  a  oreilles,  Reaumur,  Memoires,  vol.  II,  p.  63,  pi.  1,  figs.  11-15; 

p.  433,  pi.  34,  fig.  3,  1736. 

*TheGipsey  Moth,  Wilkes,  Twelve  New  Designs  of  English  Butterflies, 
1741-42. 

Roesel,  Insecten  Beliistlgung,  part  I,  p.  17,  pi.  3,  figs.  1-7,  1746. 

Schreber,  Samml.,  vol.  XIII,  p.  153,  1750. 

Baumraupe,  Schaefler,  J.  C.,  Nachricht  von  einer  Raupe,  etc.,  1752. 

Phalaena  (Bombyx)  dispar,  Linn.  Syst.  Naturae,  ed.  10,  vol.  I,  p.  501, 
1758. 

Schaefler,  J.  C.,  Der  Wunderbare  Eulenzwitter,  etc.,  1761. 
*Poda,  Insecta  Musei  Graecensis,  p.  86,  1761. 

Phalaena  Dispar,  Scopoli>  Ent.  Carniolica,  p.  197,  1763. 

Le  Zigzag,  Geoff.,  Hist.  Abregee  des  Ins.,  vol.  II,  p.  112,  No.  14,  1764. 
*Gronovius,  Zoophylacium,  vol.  II,  p.  208,  1764. 

Schaeffer,  J.  C.,  Abh.  von  Ins.,  vol.  II,  p.  315,  pi.  1,  figs.  1-8,  1764. 

Schaeffer,  J.  C.,  Icon.  Ins.  Ratisb.,  part  I,  vol.  I,  pi.  28,  figs.  3-6,  1766. 

Pbalaena  (Bombyx)  dispar,  Linn.  Syst.  Nat.,  ed.  12,  vol.  I,  p.  821,  1766. 
*Borabyx  Dispar,  Hufnagel,  Berl.  Mag.,  vol.  II,  p.  406,  pi.  3,  No.  16,  1766. 
*Bombyx  Dispar,  Hufnagel,  Berl.  Mag  ,  vol.  Ill,  p.  8,  No.  2,  1767. 

Merian,  Hist.  Generale  des  Ins.  d'Eur  ,  ed.  3,  vol.  II,  p.  5,  pi.  18,  1771. 

Bombyx  dispar,  Wilkes,  English  Moths  and  Butterflies,  pi.  42,  1773. 


258  THE   GYPSY   MOTH. 

Phalaena  dispar,  Gleditsch,  Forstwiss.,  vol.  I,  p.  310;  voL  II,  pp.  45,  81, 

227,  739,  1775. 

The  Gipsy,  Harris,  Aurelian's  Pocket  Companion,  pp.  29,  80,  1775. 
Phalaena  dispar,  Christmann,  Onomatologia  Nat.  Hist. ,  vol.  VI,  p.  350, 

1775. 

Bombyx  dispar,  Fab.,  Syst.  Ent.,  p.  570,  No.  49,  1775. 
Phalaena  dispar,  Fuessl.,  Verz.  Schweiz.  Ins.,  p.  35,  No.  660,  1775. 
Bombyx  Dispar,  Denis  and  Schiffermiiller,  Syst.  Verz.  Schm.,  p.  52,  No.  6, 

1776. 

Grosskopf,  Mueller,  O.  F.,  Zool.  Dan.  Prod.,  p.  665,  pi.  16,  figs.  2-11, 1776. 
Phalaena  dispar,  Mader,  Raupenkalender,  p.  99,  No.  282,  1777. 
Phalaena  dispar,  Fischer,  J.  B.,  Natur.  gesch.  von  Livland,  p.  151,  1778. 
Phalaena  dispar,  Fuessl.,  Mag.  fur  Liebhaber  der  Ent.,  vol.  II,  p.  286,  1778. 
Phalaena  Bombyx  dispar,  De  Geer,  Abhl.  Gesch.  der  Ins.,  vol.  II,  p.  293, 

1778. 
Phalaena  Bombyx  dispar,  Goeze,  Ent.  Beit.  Eitter,  part  III,  vol.  II,  p. 

331,  1779. 

Phalaena  dispar,  Leske,  Anfangs.  Handb.  Nat.  Gesch.,  p.  460,  No.  8,  1779. 
Eichen  und  Ulmraupe,  Glazer,  Abhl.  von  schiicll.  Raupen,  p.  39,  1780. 
Phalaena  dispar,  Rimrod,  Naturforscher,  vol.  XVI,  p.  130,  1781. 
Bombyx  dispar,  Fab.,  Species  Insectorum,  vol.  II,  p.  183,  1781. 
Bombyx  dispar,  Lang,  Verz.,  p.  86,  No.  661-664,  1782. 
Phalaena  Bombyx  Dispar,  Esper,  Schmett.,  vol.  Ill,  p.  197,  pi.  38,  figs. 

1-6,  1782. 

*  Bombyx  Dispar,  Martin,  Vade-Mecum,  Pom.  Trees,  No.  44, 1785. 
Le  zigzag,  Ernst,  Pap.  d'Europe,  vol.  IV,  p.  106,  pi.  138,  flg.  186,  a-g,  1785. 
Phalaena  dispar,  Bock,  Versuch.  Nat.  Gesch., etc.,  vol.  V.pp.  29-32,  1785. 
*Fourc.,  Entomologia  Parisiensis,  p.  261,  No.  14,  1785. 
Bombyx  dispar,  Fab.,  Mantissa  Insectorum,  vol.  II,  p.  117,  1787. 
Borowski,  Naturgeschichte  Theirreichs.,  vol.  VII,  p.  97,  1786. 
Borowski,  Naturgeschichte  Theirreichs.,  vol.  VIII,  p.  77,  1787. 
*De  Villers,  Ent.  Linnaei,  vol.  II,  p.  144,  1789. 
Bombyx  dispar,  Vieweg,  Tab.  Verzeichniss,  vol.  I,  p.  64,  1789. 
Bombyx  dispar,  Lodi,  Opuscol.  scelt.,  vol.  XII,  p.  183,  1789. 
Bombyx  Dispar,  Borkh.,  Eur.  Schm.,  vol.  Ill,  p.  312,  No.  118,  1790. 
Bombyx  disparate,  Oliv.  Ency.  Meth.,  vol.  Ill,  p.  .69,  1790. 
Rossi,  Fauna  Etrusca,  vol.  II,  p.  170,  1790. 
Phalaena  Bombyx  Dispar,  Preyssler,  Verz.  bomlscher  Insecten,  p.  41, 

1790. 

Sepp,  Nederlandische  Insecten,  vol.  Ill,  p.  5,  pi.  2,  3, 1791  (?). 
Phalaena  Bombyx  Dispar,  Schwarz,  Raupenkalender,  pp.  60,  224,  377, 1791. 
Phalaena  Bombyx  dispar,' Brahm,  Ins.  Kal.  II,  p.  517,  No.  378;  p.  739,  No. 

24,  1791. 

*Hennert,  Raupenfrass  und  Windbruch,  1791. 
Bombyx  dispar,  Borkh.,  Rhein.  Mag.,  vol.  I,  p.  334,  1791-94. 
Bombyx  dispar,  Fab.,  Ent.  Syst.,  vol.  Ill,  part  I,  p.  437,  1793. 
Phalaena  Bombyx  Dispar,  Pezolds,  Mitteldie  uns  Schad.,  etc.,  vol.  II,  flg. 

8,  1794. 

Borabyx  dispar,  Panzer,  Fauna  Germ.,  vol.  II,  pp.  22,  23,  1794. 
Phalaena  Dispar,  Berk.,  Synop.  Nat.  Hist.,  Gr.  Brit,  and  Ire.,  vol.  I,  p.  136, 

1795. 


BIBLIOGRAPHY.  259 

Phalaena  Dispar,  Don.,  Nat.  Hist.  Br.  Ins.,  vol.  V,  p.  67,  pi.  163  (Gipsey 

Moth).  1796. 
Bombyx  Dispar,  Hub.,  Samml.  Bomb.,  p.  121,  pi.  19,  figs.  75  male,  76 

female,  1800  (?)• 

Bombyx  Dispar,  Illiger's  edition,  Wien  Verz.,  vol.  I,  p.  75,  1801. 
Laria  dispar,  Schrank,  Faun.  Boica,  vol.  II,  part  1,  p.  256;  part  2,  p.  151, 

1801-02. 
var.  (?)  a,  Bombyx  disparina,  von  Mueller,  Fauna  Silesiaca,  part  III,  vol. 

I,  1802. 
*Phalaena  Bombyx  dispar,  Stewart,  Elements  of  Nat.  Hist.,  vol.  II,  p.  150, 

1802. 

Bombyx  disparus,  Ha  worth,  Lep.  Brit.,  p.  88,  1803. 

Phalaena  dispar,  Blumenbach,  Manuel  d'Histoire  Nat.,  vol.  I,  p.  465,  1803. 
Stammphalane,  Goeze,  Naturgeschichte  der  Europais.,  vol.  IX,  p.  569, 

1803. 
Phalaena  Bombyx  Dispar,  Bechstein,  Forstinseckten,  p.  369,  pi.  6,  fig.  1, 

a-e,  1804. 

Bombyx  dispar,  Panzer,  Syst.  Nomen.,  p.  40,  1804. 
Bombyx  dispar,  Latreille,  Hist.  Nat.  des  Crust  et  Ins.,  vol.  XIV,  p.  185, 

1805. 

Bombyx  Dispar,  Linn.,  Syst.  Nat.,  Turton  edition,  vol.  Ill,  p.  207,  1806. 
Bombyx  Dispar,  Hub.,  Ges.  Europ.  Schm.,  pi.  37,  fig.  2,  a,  6,  c,  1806-18. 
Liparis  Dispar,  Ochs.,  Schm.  Eur.,  vol.  Ill,  p..  195,  1810. 
Phalaena  Dispar,  Blumenbach,  Abbild.  Nat.  Hist.  Gegenstand,  p.  370,  1810. 
Bombyx  disparate,  Latreille,  Crustaces,  Arach.  et  Ins.,  pi.  8,  fig.  2,  1810. 
Laria  Dispar,  Leach,  New  Edinburgh  Ency.,  Article  Entomology,  p.  721, 

1815. 
Phalaena  Dispar,  Salisbury,  Hints  to  Propr.  of  Orchards,  p.  67,  pi.  1,  figs. 

10, 11,  1816. 
Sericaria  dispar,  Latreille,  Le  Regne  Animal,  vol.  II,  p.  269 ;  Atlas,  pi.  152, 

1817. 

Bombyx  disparate,  Latreille,  Le  Regne  Animal,  vol.  Ill,  p.  568,  1817. 
Liparis  Dispar,  Zincken,  Germar's  Mag.  der  Ent.,  vol.  Ill,  p.  431,  1818. 
Liparis  dispar,  Samouelle,  Ent.  Com.,  p.  246  (Gipsey  Moth),  1819. 
Liparis  Dispar,  Godart,  Hist.  Nat.,  vol.  IV,  p.  256,  pi.  25,  figs.  1,  2,  1822. 
Porthetria  Dispar,  Hub.,  Verz.  bek.  Schmett.,  p.  160,  1822  (?). 
Bombyce  disparate,  Dumeril,  Considerat.  General.,  pi.  45,  fig.  3,  1823. 
*  Laria  dispar,  Meig.,  Handb.  fur  Schm.,  p.  122,  pi.  47,  1827. 
Hypogymna  dispar,  Daudville,  Ann.  Soc.  d'Hort.  Paris,  vol.  Ill,  p.  98, 

1828. 
Hypogymna  dispar,  Daudville,  Ann.  Soc.  d'Hort.  Paris,  vol.  V,  pp.  204, 

324,  1829. 

Bombyx  dispar,  J.  M.,  Gardener's  Mag.,  vol.  V,  p.  204,  1829. 
Hypogymna  dispar,  Steph.,  111.  Br.  Ent.  Haust.,  vol.  II,  p.  56,  1829. 
*Liparis  dispar,  Klug.,  Verhandl.  deGesell,  Naturf.  Freunde,  pp.  363,  369, 

pi.  1,  fig.  20,  1829. 

Hypogymna  dispar,  Steph.,  Cat.  Ins.  Haust.,  p.  50,  1829. 
Hypogymna  dispar,  Rennie.Libr.  of  Entert.  Knowl.,  vol.  II,  pp.  79-82, 1830. 
Sericaria  dispar,  Latreille,  Animal  Kingdom,  vol.  IV,  p.  201,  1831. 
Liparis  dispar,  Bdv.,  Coll.  Icon,  et  Hist,  des  Chenilles  d'Eur.,  pi.  IX,  figs. 

3,  4,  1832. 


260  THE   GYPSY   MOTH. 

Bombyx  dispar,  Brown,  Book  of  Butterflies,  vol.  I,  p.  52,  1832. 
*  Liparis  dispar,  Dup.  et  Guen.,  Icon,  de  1'Hist.  Nat.  Chenilles,  vol.  II,  pi. 

8,  figs.  2-6,  1832. 

Liparis  dispar,  Godart,  Icon,  des  Chenilles,  les  Bombycites,  pi.  8,  1832. 
*Hypogymna  dispar,  Rennie,  Conspectus  of  Butterflies  and  Moths,  p.  39, 

1832. 
Phalaena  Bombyx  dispar,  Anon.,  Ann.  de  1'Inst.  Hort.  Fromont,  vol.  V, 

p.  811,  1833. 

Liparis  dispar,  Silb.,  Revue  Entomologique,  ser.  I,  vol.  I,  p.  80,  1833. 
Liparis  Dispar,  Bouche,  Nat.  Gesch.  der  Ins.,  Lieberung  I,  p.  106,  1834. 
Liparis  dispar,  Burm.,  Manual  of  Entomology,  p.  313,  1836. 
Hypogymna  dispar,  Duncan,  Naturalist's  Library,  vol.  IV,  p.  206,  1836. 
Liparis  dispar,  Lacordaire,  Manual  of  Entomology,  p.  312,  1836. 
Bombyx  dispar,  Sepp,  title-page,  vol.  V,  aberr.  male,  1836. 
Liparis  dispar,  De  Selys,  Cat.  Lep.  de  la  Belg.,  p.  28,  1837. 
Liparis  dispar,  Krause,  Arbeit.  Schles.  Gesell.  f.  vaterl.  Kultur,  p.  110, 1837. 
Liparis  dispar,  Boie,  Naturhistorisk  Tidskrift,  vol.  I,  p.  522,  1837. 
Liparis  dispar,  Audouin,  Naturhistorisk  Tidskrift,  vol.  II,  p.  304,  1838. 
Liparis  dispar,  Lacordaire,  Intro,  a  1'Entomologie,  vol.  II,  pp.  371,  383, 

1838. 

*Bombyce  disparate,  Debia,  Rec.  Agr.  Soc.  Dept.,  p.  156,  pi.  1,  1838. 
Hypogymna  dispar,  Curt.,  Br.  Ent.,  vol.  XVI,  p.  767  (Gypsy  Moth),  1839. 
Bombyce  disparate,  Lamarck,  Animaux  sans  Vertebres,  vol.  Ill,  p.  77, 

1839. 

Bombyx  dispar,  Dejean,  Ann.  Soc.  Ent.  France,  vol.  VIII,  p.  41,  1839. 
Bombyx  dispar,  Reichenbacka,  Galerya,  Obr.  Zwier.  Hist.  Nat.,  vol.  II, 

p.  302,  1839. 

Bombyx  (Liparis)  dispar,  Nordl.,  Stett.  Ent.  Zeit.,vol.  I,  p.  266,  1840. 
Bombyx  (Liparis)  dispar,  Kollar,  Inj.  Ins.,  English  ed.,  p.  26,  1840. 
Phalaena  Bombyx  dispar,  Ratz.,  Forst.  Ins.,  vol.  II,  p.  Ill,  pi.  5,  figs. 

IF,  IF',  IK,  1L,  1C,  1840. 

Liparis  dispar,  Schultze,  Stett.  Ent.  Zeit.,  vol.  I,  p.  49,  1840. 
Hypogymna  dispar,  Westw  ,  Int.  to  Modern  Classif.  Ins.,  p.  384,  1840. 
Bombyx  dispar,  Fouscol.,  Mem.  de  1'Acad.  de  Sci.  Agr.  Arts,  etc.,  vol.  V, 

p.  85,  1840. 

Liparis  Dispar,  Hering,  Stett.  Ent.  Zeit.,  vol.  Ill,  p.  9,  1842. 
Liparis  dispar,  Joly,  Revue  Zoologie,  vol.  V,  p.  115,  1842. 
Porthetria  dispar,  Humphrey  and  Westw.,  Br.  Moths  and  their  Transf., 

vol.  I,  p.  17,  figs.  1-3,  1843. 

Liparis  Dispar,  Duponchel,  Cat.  Methodique,  p.  68,  1844. 
Liparis  Dispar,  Eversmann,  Fauna  Lep.  Volgo-Ural,  p.  142,  1844. 
Liparis  Dispar,  Herrich-Schaeffer,  Eur.  Schm.,  vol.  II,  p.  135,  1845. 
Liparis  dispar,  Villa,  Memoria  deg  Insetti  carnivori,  p.  59,  1845. 
Liparis  dispar,  Ratz.,  Stett.  Ent.  Zeit.,  vol.  VII,  p.  37,  1846. 
Liparis  dispar,  Bellier,  Ann.  Soc.  Ent.  France,  vol.  XVI,  p.  98,  1847. 
Bombyx  dispar,  Johnson,  Diet,  of  Modern  Gardening,  p.  92,  1847. 
Bombyx  dispar,  Nordl.,  Stett.  Ent.  Zeit.,  vol.  IX,  p.  266,  1848. 
Liparis  dispar,  Bellier,  Bull.  Soc.  Ent.  France,  ser.  II,  vol.  VII,  p.  173, 

pi.  6,  1849. 

Liparis  dispar,  Guen.,  Hist.  Nat.  Nocturnes,  vol.  II,  pi.  8,  flg.  2,  o,  b,  1849. 
Liparis  dispar,  Bellier,  Bull.  Soc.  Ent.  France,  ser.  II,  vol.  X,  p.  73,  1852. 
Liparis  dispar,  Filippi,  Stett.  Ent.  Zeit.,  vol.  XIII,  p.  263,  1852. 


BIBLIOGRAPHY.  261 

Liparis  Dispar,  Speyer,  Stett.  Ent.  Zeit.,  vol.  XIII,  p.  318,  1852. 
Lymantria  dispar,  Walk.,  Cat.  Lep.  Het.,  part  IV,  p.  872,  1855. 
Bombyx  dispar,  Sepp,  title-page,  vol.  VIII,  aberr.  male,  1855-60. 
Liparis  dispar,  DeSelys  (?),  Ann.  Soc.  Ent.  Belg.,  vol.  I,  p.  52,  1857. 
Hypogymna  dispar,  Stainton,  Manual,  vol.  I,  p.  130,  1857. 
Hypogymna  Dispar,  Humphrey,  Gen.  Br.  Moths,  p.  27,  pi.  10,  figs.  1-10, 

1858. 
Ocneria  dispar,  Speyer,  Die  Geograph.  Verbreit.  Schm.,  part  I,  p.  401, 

1858. 
Hypogymna  Dispar,  Kearley,  Ent.  Weekly  Intelligencer,  vol.  IV,  p.  192, 

1858. 

Rosenspinner,  Hermann,  Der  Raupen  und  Schmetterlingsjager,  p.  81,  1859. 
Liparis  dispar,  Hagen,  Stett.  Ent.  Zeit.,  vol.  XXI,  p.  34,  1860. 
Liparis  dispar,  Leunis,  Zoologie,  p.  543,  1860. 
Hypogymna  dispar,  Batty,  Ent.  Weekly  Intelligencer,  vol.  VIII,  p.  141, 

1860. 
Hypogymna  dispar,  Stanley,  Ent.  Weekly  Intelligencer,  vol.  VIII,  p.  187, 

1860. 
Schwammspinner,  Pueschl.,  Kurzgefasste  Forst.  Ency.,  Leipzic,  pp.  186, 

298,  1860. 

Liparis  dispar,  Mulder,  Tijdschrift  voor  Ent.,  ser.  I,  vol.  II,  p.  2,  1860. 
Liparis  dispar,  Goreau,  Ins.  Nuis.  aux  Arbres  Fruitiers,  p.  89,  1861. 
Liparis  dispar,  Hagen,  Stett.  Ent.  Zeit.,  vol.  XXII,  p.  59,  1861. 
Liparis  Dispar,  Rathke,  Stett.  Ent.  Zeit.,  vol.  XXII,  p.  238,  1861. 
Bombyx  dispar,  Siebold,  Stett.  Ent.  Zeit.,  vol.  XXII,  p.  443,  1861. 
Liparis  dispar,  Dobner,  Zool.,  vol.  II,  p.  345,  1862. 
Ocneria  dispar,  Speyer,  Die  Geog.  Verbreit.  Schm.,  part  II,  p.  287,  Nach- 

trage,  1862. 

Liparis  dispar,  Keller,  Stett.  Ent.  Zeit.,  vol.  XXIII,  p.  284,  1862. 
Liparis  dispar,  Prittw.,  Stett.  Ent.  Zeit.,  vol.  XXIII,  p.  382,  1862. 
Liparis  dispar,  Newm.,  Proc.  Ent.  Soc.  Lond.,  pp.  70,  77,  1862. 
Ocneria  dispar,  Jaggi,  Bull.  Soc.  Ent.  Suisse,  vol.  I,  p.  313,  1862-65. 
Liparis  dispar,  Bremer,  Lepidopteren  Ost-Siberiens,  p.  41,  1864. 
Liparis  dispar,  Bdv.,  Journ.  Soc.  Hort.  France,  p.  447,  1864. 
Sericaria  dispar,  Mulder,  Tijdschrift  voor  Ent.,  ser.  I,  vol.  VII,  p.  125, 

1864. 
Liparis  dispar,  Keppen,  Horae  Soc.  Ent.  Rossicae,  pp.  81,  257,  287,  294, 

1865. 
Ocneria  dispar,  Tieffenbach,  Berl.  Ent.  Zeit.,  vol.  IX,  p.  413,  pi.  3,  fig.  8, 

1865. 

Bombyx  dispar,  Samuels,  Agriculture  of  Mass.,  p.  116,  1865-66. 
Bombyx  dispar,  Ratz.,  Die  Waldverderbniss,  vol.  I,  pp.  113,  226,  1866. 
Ocneria  dispar,  Maurisseu,  Tijdschrift  voor  Ent.,  ser.  II,  vol.  IX,  p.  176, 

1866. 
Liparis  dispar,  Brehm  and  Rossmassler,  Die  Thiere  des  Walden,  vol.  II, 

p.  107,  fig.  11 ;  p.  108,  figs,  a-d,  1866-67. 

Ocneria  dispar,  Pfutzner,  Berl.  Ent.  Zeit.,  vol.  XI,  p.  199,  1867t 
Liparis  dispar,  Westwood,  Proc.  Ent.  Soc.  Lond.,  pp.  44,  49,  1867. 
Ocneria  dispar,  de  Gavere,  Tijdschrift  voor  Ent.,  ser.  II,  vol.  X,  p.  200, 

1867. 

Bombyx  dispar,  Rudzky,  Horae  Soc.  Ent.  Rossicae,  vol.  V,  p.  12,  1867. 
*0cneria  Dispar,  var.  Disparina,  Snell.,  Vlind.  Nederl.  Macro.,  p.  175, 1867. 


262  THE   GYPSY  MOTH. 

Liparis  dispar,  Bdv. ,  Essai  sur  1'Entomologie  Horticole,  1867. 

Bombyx  dispar,  Rat/..,  Die  Waldverderbniss,  vol.  II,  pp.  12-151,  etc., 

1868. 
Bombyx  dispar,  Berce,  Bull.  Ent.  Soc.  France,  ser.  Ill,  vol.  VIII,  p.  61, 

1868. 

Liparis  dispar,  Dorfmeister,  Stett.  Ent.  Zeit.,  vol.  XXIX,  p.  183,  1868. 
Liparis  dispar,  Charault,  Bull.  Soc.  Agr.  Sci.  Arts,  vol.  XI,  pp.  688,  697, 

1868. 
Bombyx  dispar,  Senft,  Systematische  Bestimm.  Deutsch.,  p.  77,  pi.  1,  2, 

3,  5,  1868. 
Liparis  dispar,  Girard,  Bull.  Soc.  Ent.  France,  ser.  Ill,  vol.  IX,  p.  69, 

1869. 

Liparis  dispar,  Bull,  della  Soc.  Ent.  Italiana,  vol.  I,  p.  69,  1869. 
Bombyx  dispar,  Bull,  della  Soc.  Ent.  Italiana,  vol.  I,  pp.  78-81,  1869. 
Liparis  dispar,  Charault,  Bull.  Soc.  Agr.  Sci.  Arts  of  Sarthe,  vol.  XII, 

p.  316,  1869. 

Liparis  Dispar,  Kieferstein,  Stett.  Ent.  Zeit.,  vol.  XXX,  p.  229,  1869. 
Ocneria  dispar,  Speyer,  Stett.  Ent  Zeit.,  vol.  XXX,  p.  246,  1869. 
Phalaena  Bombyx  dispar,  Ratz.,  Die  Waldverderber,  p.  184,  pi.  5,  flg.  1, 

1869. 

Liparis  dispar,  Newm.,  British  Moths,  p.  37,  1869. 
Ocneria  dispar,  Jaggi,  Bull.  Soc.  Ent.  Suisse,  vol.  Ill,  p.  100,  1869-70. 
Hypogymna  dispar,  Riley,  Annual  Rep.  Missouri,  vol.  II,  p.  10,  1870. 
Hypogymna  dispar,  Riley,  Am.  Ent.,  vol.  II,  p.  Ill,  1870. 
Liparis  dispar,  Bargagli,  Bull,  della  Soc.  Ent.  Italiana,  vol.  II,  pp.  208, 

262,  279,  1870. 
Bombyx  dispar,  Bazin,  Bull.  Soc.  Hist,  de  1'Yonne,  ser.  I,  vol.  XXIV,  pp. 

11-20,  1870. 

Ocneria  dispar,  Tratman,  The  Ent.,  vol.  V,  p.  172,  1870. 
Ocneria  dispar,  Spiller,  The  Ent.,  vol.  V,  p.  183,  1870. 
Ocneria  dispar,  Davidson,  The  Ent.,  vol.  V,  p.  213,  1870. 
Ocneria  dispar,  Button,  The  Ent.,  vol.  V,  p.  393,  1870. 
Ocneria  dispar,  Bowyer,  The  Ent.,  vol.  V,  p.  452,  1870. 
Ocneria  dispar,  Hylaerts,  Tijdschrift  voor  Ent.,  ser.  II,  vol.  XIII,  p.  148, 

1870. 
Ocneria  Dispar,  Kirby,  Cassell's  Eur.  But.  and  Moths,  p.  110,  pi.  25,  flgs. 

a-c,  1870  (?). 

Liparis  dispar,  Briggs,  Proc.  Ent.  Soc.  Lond.,  p.  9,  1871. 
Liparis  dispar,  Dohrn,  Stett.  Ent.  Zeit.,  vol.  XXXII,  p.  29,  1871. 
Liparis  dispar,  Dei,  Bull,  della  Soc.  Ent.  Italiana,  vol.  Ill,  pp.  75,  360, 

1871. 
Ocneria  dispar,  Hylaerts,  Tijdschrift  voor  EnJ.,  ser.  II,  vol.  XIV,  p.  38, 

1871. 
Bombyx  dispar,  Siebold,  Bull,  della  Soc.  Ent.  Italiana,  vol.  IV,  p.  121, 

1872. 

Liparis  dispar,  Plateau,  Bull,  della  Soc.  Ent.  Italiana,  vol.  IV,  p.  197, 1872. 
Liparis  dispar,  Vinercati,  Bull,  della  Soc.  Ent.  Italiana,  vol.  IV,  p.  302, 

1872. 
Liparis  dispar,  Ghiliani,  Bull,  della  Soc.  Ent.  Italiana,  vol.  IV,  p.  365, 

1872. 
Liparis  dispar,  Lelievre,  Feuilles  des  Jeunes  Naturallstes,  vol.  Ill,  p.  77, 

1872. 


BIBLIOGRAPHY.  263 

Ocneria  dispar,  Hagen,  Stett.  Ent.  Zeit.,  vol.  XXXIII,  p.  389,  1872. 
Ocneria  dispar,  Nickerl.,  Verb.  z.  B.  Wien.,  vol.  XXII,  p.  729,  1872. 
Phalaena  Bombyx  dispar,  Kauschinger,  Die  Lehre  vom  Walds.,  p.  65,  fig. 

13,  1872. 

Liparis  dispar,  Greville,  The  Ent.,  vol.  VI,  p.  190,  1872. 
Liparis  dispar,  Clifford,  The  Ent.,  vol.  VI,  p.  289,  1872. 
Liparis  dispar,  Standish,  The  Ent.,  vol.  VI,  p.  364,  1872. 
Psilura  dispar,  Frey  and  Wullsch.,  Bull.  Ent.  Soc.  Suisse,  vol.  IV,  p.  268, 

1873-76. 
Ocneria  dispar,  Kigg.-Stehlin,  Bull.  Ent.  Soc.  Suisse,  vol.  IV,  p.  597, 

1873-76. 

Liparis  dispar,  Rondani,  Bull,  della  Soc.  Ent.  Italiana,  vol.  V,  p.  164,  1873, 
Ocneria  dispar,  Dihrik,  Stett.  Ent.  Zeit.,  vol.  XXXIV,  p.  114,  1873. 
Liparis  dispar,  Kaltenbach,  Die  Pflanzenfeinde,  pp.  74,  158,  185,205,  217, 

429,  1874. 
Ocneria  dispar,  Kaltenbach,  Die  Pflanzenfeinde,  pp.  537,  548,  569,  594, 

613,  626,  634,  640,  651,  1874. 

*Liparis  dispar,  Barrett,  Trans.  Norwich  Soc.,  suppl.,  p.  14,  1874. 
Liparis  dispar,  Plateau,  Recherches  sur  Digestion,  etc.,  p.  84,  1874. 
Bombyx  (Liparis)  dispar,  Tasch.,  Ent.  f.  Giirt.  und  Garten,  p.  219,  figs. 

58-61,  1874. 
Liparis  dispar,  Targ.  Tozz.,  Bull,  della  Soc.  Ent.  Italiana,  vol.  VI,  p.  86, 

1874. 

Liparis  dispar,  Dubois,  Lep.  de  Belgique,  vol.  II,  p.  170,  1874. 
Ocneria  dispar,  Lelievre,  Feuilles  des  Jeunes  Naturalistes,  vol.  V,  pp. 

97-100,  1874. 

Liparis  dispar,  Girard,  Bull.  Soc.  Ent.  France,  suppl.,  vol.  IV,  p.  129, 1874. 
Liparis  dispar,  Girard,  Bull.  Soc.  Ent.  France,  suppl.,  vol.  V,  p.  114, 1875. 
Liparis  dispar,  Gaschet,  Bull.  Ent.  Soc.  France,  ser.  V,  vol.  V,  p.  ccxiii, 

1875. 

Chenilles  a  oreilles,  Ernst,  Pap.  de  1'Europe,  vol.  IV,  p.  106,  pi.  138, 1875. 
Liparis  dispar,  Villa,  Lo.  Studio  Insetti  in  Lombardia,  1876. 
Bombyx  dispar,  Blanchere,  Rav.  des  For.  et  Arbres  d' Align.,  pp.  178,  853, 

figs.  92,  93,  153,  154,  155,  156,  1876. 

Ocneria  dispar,  Weithofer,  Verb,  ver  Briinn.,  vol.  XV,  p.  39,  1876. 
Liparis  dispar,  var.  b,  bordigalensis  or  disparoides,  Mab.  and  Gasch. ,  Bull. 

et  Ann.  Soc.  Ent.  France,  ser.  V,  vol.  VI,  pp.  9,  521,  1876. 
Liparis  dispar,  Mabille,  Bull.  Soc.  Ent.  France,  suppl.,  vol. VI,  p.  9,  1876. 
Ocneria  dispar,  Bettoni,  Considerazioni  sopra  casa,  etc.,  p.  121,  1876. 
Liparis  dispar,  Rondani,  Bull,  della  Soc.  Ent.  Italiana,  vol.  VIII,  p.  129, 

1876. 

Liparis  dispar,  Brehm,  Thierleben,  vol.  IX,  p.  15,  1877. 
*Bombyx  dispar,  Bouche,  Schvvammraupe,  Schwammspinner,  vol.  IV,  p. 

410,  1877. 

Liparis  dispar,  Rondani,  Bull,  della  Soc.  Ent.  Italiana,  vol.  IX,  p.  55,  1877. 
Liparis  dispar,  Depuisset,  Les  Paps.,  p.  248,  pi.  24,  fig.  2,  a-c,  1877. 
Ocneria  dispar,  Christoph.,  Stett.  Ent.  Zeit.,  vol.  XXXIX,  p.  408,  1878. 
Ocneria  Dispar,  Cassel,  Die  Makrolep.  der  Amgegend  Cassels,  p.  113, 1878. 
Ocneria  dispar,  Brants,  Tijd.  Ent.,  vol.  V,  p.  22,  1878. 
Liparis  dispar,  Locard,  Soc.  Agr.  Sci.  and  Arts  of  Lyons,  1878. 
Ocneria  dispar,  Enock,  The  Ent.,  vol.  XI,  p.  170,  1878. 
Ocneria  dispar,  Rondani,  Bull,  della  Soc.  Ent.  Italiana,  vol.  X,  p.  22,  1878. 


264  THE   GYPSY  MOTH. 

Ocneria  dispar,  Turati,  Bull,  della  Soc.  Ent.  Italiana,  vol.  XI,  p.  171, 1879. 
*Dickkopfspinner,  Hommerling,  Isis,  Russ.,  vol.  IV,  p.  86,  1879. 
*Liparis  dispar,  Szalkay,  Termeszet,  Fuzetek,  vol.  IV,  p.  105,  1879. 
Liparis  dispar,  Pearce,  The  Eat. ,  vol.  XII,  p.  229,  1879. 
Bombyx  dispar,  Altum,  Forstzoologie,  vol.  II,  p.  324,  1880. 
Psilura  Dispar,  Freyer,  Lep.  der  Schweiz.,  p.  94,  1880. 
"Liparis  dispar,  Slosarski,  Der  Polnische  Giirtner,  vol.  II,  pp.  69-92,  1880. 
Liparis  dispar,  Wilson,  Larvae  of  the  Brit.  Lep.,  p.  68,  pi.  12,  fig.  8, 1880. 
Ocneria  dispar,  Fiori,  Bull,  della  Soc.  Ent.  Italiana,  vol.  XII,  p.  214,  1880. 
Ocneria  dispar,  Maassen,  Stett.  Ent.  Zeit.,  vol.  XLI,  p.  168,  1880. 
Ocneria  dispar,  Hering,  Stett.  Ent.  Zeit.,  vol.  XLII,  p.  334,  1881. 
Ocneria  dispar,  Staudinger,  Stett.  Ent.  Zeit.,  vol.  XLII,  p.  406,  1881. 
Bombyx  (Liparis)  dispar,  Schm-Gobel,  Die  Schiidlichen  Forstinseckten, 

part  I,  p.  99,  fig.  95,  1881. 
Bombyx  (Liparis)  dispar,  Schm-Gobel,  Die  Schiidlichen  Forstinseckten, 

part  II,  p.  96,  1881. 

Bombyx  dispar,  Altum,  Forstzoologie,  vol.  II,  p.  324,  1881. 
Liparis  dispar,  Goossens,  Bull.  Ent.  Soc.  France,  vol.  I,  p.  232,  1881. 
Liparis  dispar,  Lucas,  Bull.  Ent.  Soc.  France,  vol.  I,  p.  148,  1881. 
Liparis  dispar,  Girard,  Bull.  Ent.  Soc.  France,  vol.  II,  1882. 
Ocneria  dispar,  Gauckler,  Katter's  Ent.  Nachtrichten,  vol.  VIII,  p.  274, 

1882. 

Liparis  dispar,  Altum,  Forstzoologie,  vol.  Ill,  p.  94,  1882. 
Ocneria  dispar,  Teich.,  Stett.  Ent.  Zeit.,  vol.  XLIV,  p.  171,  1883. 
Ocneria  dispar,  Keppen,  Injurious  Insects,  vol.  Ill,  p.  49,  1883. 
Ocneria  dispar,  Mina,  Naturalista  Sicil.  Giorna.  Sci.  Nat.,  vol.  Ill,  p.  64, 

1883. 

Ocneria  dispar,  Oudetnans,  Tijd.  Ent.,  vol.  XXVII,  p.  16,  1884. 
Ocneria  Dispar,  Horaeyer,  Stett.  Ent.  Zeit.,  vol.  XLV,  p.  424,  1884. 
Ocneria  dispar,  Tasch.,  Brehm's  Thierleben,  Inseckten,  p.  395,  figs.  1-3, 

1884. 
*Ocneria  dispar,  Kalchberg,  Naturalista  Sicil.  Giorna.  Sci.  Nat.,  vol.  IV, 

p.  55,  1884-85. 

Hypogymna  dispar,  Wood,  Animated  Creation,  vol.  Ill,  p.  423,  1885. 
Ocneria  dispar,  Bull,  della  Soc.  Ent.  Italiana,  vol.  XVII,  p.  156,  1885. 
Ocneria  dispar,  Raynor,  The  Ent.,  vol.  XVIII,  p.  243,  1885. 
Ocneria  dispar,  St.  John,  The  Ent.,  vol.  XIX,  p.  250,  1886. 
Ocneria  dispar,  Adkin,  The  Ent.,  vol.  XIX,  p.  281,  1886. 
Ocneria  dispar,  Blaber,  The  Ent.,  vol.  XIX,  p.  281,  1886. 
Ocneria  dispar,  Hall,  The  Ent.,  vol.  XIX,  p.  282,  1886. 
Ocneria  dispar,  Buckler,  Larvae  of  Brit.  Butterflies,  vol.  Ill,  p.  37,  1886. 
Liparis  dispar,  Brocchi,  Trait6  de  Zoologie  Agricole,  p.  451,  1886. 
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1886. 

Ocneria  dispar,  ab.  erebus,  Thierry,  Le  Naturalist,  vol.  VIII,  p.  237, 1886. 
Ocneria  dispar,  ab.  semiobscura,  Meig.,  Le  Naturalist,  vol.  VIII,  p.  237, 

1886. 

Ocneria  dispar,  ab.  erebus,  Meig.,  Le  Naturalist,  vol.  VIII,  p.  237,  1886. 
*The  Gypsy  Moth,  Dictionary  of  Gardening  (Insects),  vol.  II,  p.  182, 1887. 
Ocneria  dispar,  Edwards,  The  Eut.,  vol.  XX,  p.  275,  1887. 
Liparis  dispar,  Goossens,  Bull.  Ent.  Soc.  France,  ser.  VI,  vol.  VII,  p.  166, 
1887. 


BIBLIOGRAPHY.  265 

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1887. 
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fig.  63,  a-d,  1887. 

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266  THE   GYPSY  MOTH. 

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p.  34,  1892. 

Ocneria  dispar,  Bethune,  Rep.  Ent.  Soc.  Ont.,  vol.  XXIII,  p.  86,  1892. 
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1892. 

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fig.  13,  1893. 

Ocneria  dispar,  Eckstein,  Die  Kiefer,  vol.  I,  p.  22,  pi.  13,  figs.  4-9,  1893. 
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pp.  126,  207,  pi.  3,  fig.  19,  1893. 

Ocneria  dispar,  Forbush  and  Fernald,  Rep.  Mass.  Bd.  Agr.,  p.  263,  1893. 
Ocneria  dispar,  Lintn.,  Rep.  Ins.  N.  Y.,  vol.  IX,  pp.  422,  433,  440,  1893. 
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seckt.,  vol.  Ill,  1893. 

Ocneria  dispar,  Seitz,  Stett.  Ent.  Zeit.,  vol.  LIV,  p.  369,  1893. 
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1893. 

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1893. 

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Hypogymna  dispar,  Barrett,  Lep.  Brit.  Islands,  part  XX,  p.  303,  1894. 
Ocneria  dispar,  Furneaux,  Butterflies  and  Moths,  p.  227,  1894. 
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DISTRIBUTION  IN  THE  OLD    WORLD.      267 

Ocneria  dispar,  Kudzky,  Ins.  Useful  and  Inj.  to  Fruit  Trees,  pp.  9-13, 

1894. 

Ocneria  dispar,  Kane,  The  Ent.,  vol.  XXVII,  p.  15,  1894. 
Ocneria  dispar,  South,  The  Ent.,  vol.  XXVII,  p.  25,  1894. 
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The  Gypsy  Moth,  Ent.  Record,  vol.  VII,  p.  146,  1895. 
Ocneria  dispar,  Mocsary,  Termeszet.  Fuzetek,  vol.   XVIII,  pp.   67,  72, 

1895. 
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378,  1895. 

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Ocneria  dispar,  Meyrick,  Handbook  of  British  Lepidoptera,  p.  175,  1895. 

DISTRIBUTION  IN  OTHER  COUNTRIES. 

The  gypsy  moth  has  a  wide  distribution  in  the  old  world. 
Speyer,  in  "  Die  Geographische  Verbreitung  der  Schmetter- 
linge,"  published  in  1858-62,  Vol.  I,  page  401,  and  Vol.  II, 
page  287,  informs  us  that  it  extends  over  the  entire  region, 
from  the  lowlands  to  the  highlands,  through  middle  and 
southern  Europe,  western  Asia  and  northern  Africa,  reach- 
ing from  Stockholm  on  the  north  to  Algiers  on  the  south, 
England  on  the  west,  the  Altai  Mountains  and  the  Caspian 
Sea  on  the  east.  It  extends  also  into  eastern  Asia,  including 
Japan ;  and  the  tropics,  Neitner  having  found  it  in  Ceylon. 

Bremer,  in  his  "  Lepidopteren  Ost-Siberiens,"  published 
in  1864,  reported  it  in  south-eastern  Siberia.  Staudinger, 
in  his  "Catalog der  Europseischen Faunengebiets," published 
in  1871,  gives  for  the  distribution  of  the  gypsy  moth  the 
entire  territory,  except  the  northern  countries,  including 
southern  Sweden  and  England.  He  also  doubtfully  includes 
Livonia.  Grseser  states  that  the  young  caterpillars  of  this 
species  were  very  common  in  the  early  part  of  June,  1881, 
near  Vladivostock,  Siberia.  He  further  states  that  the  cater- 
pillars in  Anioor  have  a  very  different  appearance  from  those 
in  Europe,  the  prevailing  color  being  yellow ;  but  all  the 
nioths  bred  from  these  caterpillars  were  entirely  like  those 
of  Europe,  "Berlin  Ent.  Zeits.,"  Vol.  XXXII.  In  1861, 
Hoineyer  reported  the  gypsy  moth  on  the  Island  of  Majorca 
in  great  abundance,  destroying  both  deciduous  and  evergreen 
trees.  In  the  "Entomologist's  Monthly  Magazine,"  Vol. 


268  THE  GYPSY  MOTH. 

XXV,  page  65,  1888,  Mr.  J.  J.  Walker  reported  that  he 
found  this  insect  in  great  abundance  in  southern  Spain,  near 
the  village  of  Los  Barrios.  In  a  work  on  "  Injurious  In- 
sects," by  Theodore  Keppen,  published  in  Russian  and  trans- 
lated for  me  by  Dr.  F.  B.  Stephenson,  U.  S.  N.f  it  is  stated 
that  this  insect  occurs  in  the  central  and  southern  parts  of 
Russia,  in  the  Caucasus  and  all  southern  Siberia,  but  it  does 
not  occur  in  the  vicinity  of  St.  Petersburg.  He  further  states 
that,  according  to  Nolken,  it  does  not  appear  in  the  Baltic 
Provinces,  but  has  been  found  occasionally  in  Livonia,  and, 
on  the  authority  of  Albrecht,  it  is  very  common  in  the 
vicinity  of  Moscow.  Romanoff,  in  the  sixth  volume  of  his 
"  Mernoires  sur  les  Lepidopteres,"  reports  it  in  North  China, 
and  I  have  in  my  collection  three  male  gypsy  moths  from 
Pekin,  China,  received  from  Dr.  O.  Staudinger.  In  a  letter 
from  Dr.  Ritzema-Boz  of  Holland,  dated  Sept.  3,  1895,  he 
writes,  '  *  This  insect  is  common  in  Holland  and  also  in  all 
western  Europe." 

THE  GYPSY  MOTH  IN  ENGLAND. 

The  earliest  information  that  I  have  found  of  the  presence 
of  the  gypsy  moth  in  England,  is  given  by  Wilkes,  in  his 
work  entitled  "Twelve  New  Designs  of  English  Butterflies," 
published  in  London  in  1741-42,  with  twelve  plates,  but  with- 
out text.  Plate  X,  Fig.  2,  represents  the  insect  under  the 
name  "The  Gipsey  Moth." 

Harris  described  it  in  his  "  Aurelian's  Pocket  Companion," 
published  in  1775.  Donovan,  in  his  "Natural  History  of 
British  Insects,"  Vol.  V,  published  in  1796,  figures  this  insect 
on  Plate  CLXIII,  and  describes  it  on  pages  67-69,  calling 
it  the  "Gipsey  Moth."  In  his  account  he  says  :  "That  the 
Phalena  Dispar  was  not  uncommonly  scarce  about  fifteen 
years  ago,  is  evident  from  this  circumstance,  few  collections 
of  British  insects  that  were  in  the  hands  of  eminent  collec- 
tors are  without  an  English  specimen,  which  was  procured 
about  that  time."  From  his  further  account  we  infer  that 
he  considered  it  a  rare  insect  in  England.  Haworth,  in  his 
"Lepidoptera  Britannica,"  page  88,  published  in  1803,  calls 
it  Bombyx  disparus,  and  for  a  common  name  "The  Gipsy," 
and  says  it  is  very  rare.  Salisbury,  in  his  "Hints  to  Pro- 


THE   GYPSY  MOTH  IN  ENGLAND.          269 

prietors  of  Orchards,"  published  in  London  in  1816,  gives 
the  fullest  and  most  complete  account  of  the  gypsy  moth  that 
I  have  seen  in  English  up  to  that  date.  He  states  that  this 
caterpillar  is  common  in  gardens  and  woods,  where  it  does 
considerable  damage. 

Stephens,  in  Vol.  II,  page  56,  "Illustrations  of  British 
Entomology,"  Haustellata,  1829,  says  it  is  not  common  near 
London,  but  appears  to  abound  in  the  fens  of  Huntingdonshire. 
He  also  refers  to  the  statement  that  it  was  introduced  into 
Britain  by  eggs  imported  by  Mr.  Collinson,  but  says  that  the 
abundance  with  which  it  occurs  near  Whittlesea,  and  the  dis- 
similarity of  the  indigenous  specimens  (which  are  invaria- 
bly paler,  with  stronger  markings)  to  the  foreign,  sufficiently 
refute  the  opinion. 

Curtis,  in  his  ''British  Entomology,"  Vol.  XVI,  1839, 
alludes  to  the  scarcity  of  this  species  in  the  time  of  Donovan, 
and  speaks  of  finding  them  in  considerable  numbers,  when  a 
boy,  in  the  marshes  at  Horning,  in  Norfolk.  Mr.  Stainton, 
in  his  "Manual  of  Butterflies  and  Moths,"  Vol.  I,  page  130, 
1857,  says,  "It  is  found  plentifully  in  fenny  districts,  but  is 
not  generally  common."  George  Kearley,  in  the  "Ento- 
mologist's Weekly  Intelligencer,"  Vol.  IV,  page  192,  1858, 
speaks  of  the  gradual  disappearance  of  the  gypsy  moth  in 
England,  and  states  that  it  was  claimed  by  some  to  have 
actually  become  extinct  in  that  country.  Mr.  Richard  South, 
in  the  "Entomologist,"  Vol.  XXV,  page  259,  1892,  states 
that  entomologists  in  1870  seem  to  have  been  a  little  troubled 
about  the  right  of  the  gypsy  moth  to  be  considered  a  British 
insect,  referring,  of  course,  to  those  caterpillars  or  imagoes 
which  were  then  found  at  large.  He  further  says,  after  speak- 
ing of  specimens  having  been  found  from  time  to  time,  that 
there  is  no  reasonable  doubt  that  this  species  is  extinct  in 
England;  "that  somewhere  about  the  fourth  decade  of  this 
century,  the  species  began  to  decrease  in  numbers,  and  that 
toward  the  end  of  the  fifties  it  had  practically  ceased  to  exist 
as  a  wildling  in  this  country." 

Numerous  attempts  have  been  made  to  introduce  this  insect 
into  England  again,  but  they  do  not  appear  to  have  been 
successful.  Many  entomologists  have  bred  it  in  confinement, 
continuing  until  it  can  now  be  regarded  only  as  a  semi-do- 


270  THE  GYPSY  MOTH. 

inesticated  species  in  England  ;  and  complete  degeneration  of 
the  stock,  by  the  process  known  as  "in-and-in  breeding,"  is 
possibly  averted  by  the  periodical  introduction  of  eggs  from 
the  Continent. 

The  late  Mr.  J.  Jenner  Weir,  in  a  letter  to  "  Insect  Life," 
Vol.  IV,  page  138,  1891,  said  that  the  gypsy  moth  had  been 
unintentionally  exterminated  in  England,  and  further  writes, 
* '  I  think  the  gypsy  moth  must  have  been  destroyed  simply 
by  collectors."  Mr.  C.  G.  Barrett,  in  his  "  Lepidoptera  of 
the  British  Islands,"  Vol.  II,  page  303,  1894,  gives  a  very 
good  history  of  the  occurrence  of  this  moth  in  England  and 
of  its  probable  disappearance,  but  without  assigning  any 
cause  for  such  disappearance. 

Mr.  C.  Nicholson  read  a  paper  on  the  life-history  of  the 
gypsy  moth,  before  the  City  of  London  Entomological  and 
Natural  History  Society,  Sept.  18,  1894,  in  which  he  pro- 
posed for  discussion,  among  others,  the  question  why  this  in- 
sect had  become  extinct  in  England.  Mr.  J.  "W.  Tutt  gave  it 
as  his  opinion  that  it  was  because  the  insect  was  not  a  native. 
"  Its  whole  history  proved  it  to  be  an  imported  species,  even 
when  it  first  became  known.  Thousands  of  specimens  in  all 
stages  had  been  set  loose  in  various  parts  of  the  country, 
but,  with  the  exception  of  an  odd  specimen  here  and  there, 
no  specimens  were  taken  wild.  Its  abundance  in  the  fens  for 
a  year  or  two  simply  pointed  to  the  care  with  which  it  was 
put  out,  and  to  the  temporary  existence  of  favorable  condi- 
tions. There  are  thousands  of  acres  of  land,  to  all  intents 
and  purposes  fitted  for  its  establishment  here,  but  it —  pos- 
sibly the  agriculturists  would  say  fortunately  —  will  not 
establish  itself." 

The  history  of  the  gypsy  moth  in  the  United  States  does 
not  seem  to  lend  force  to  the  view  taken  by  Mr.  Tutt,  as 
much  as  we  wish  it  might  prove  true,  for  it  seems  to  thrive 
as  well  here  as  in  any  part  of  the  old  world.  America  is 
indebted  to  Europe  for  a  long  list  of  insect  pests,  many  of 
which  are  far  more  injurious,  because  of  their  unrestricted 
increase,  than  in  their  native  country ;  notable  among  these 
are  the  currant  saw-fly  (Nematus  ribesii),  the  larch  saw-fly 
(Nemalus  erichsonii),  the  cabbage  butterfly  (Pieris  ropce), 
the  Buffalo  carpet-beetle  (Anthrenus  scrophularice)  and  many 


THE   GYPSY  MOTH  IN  ENGLAND.          271 

others,  none  of  which  show  any  indications  of  a  decline  in  a 
foreign  country.  The  idea  of  Mr.  Weir,  that  they  were  de- 
stroyed in  England  by  collectors,  hardly  seems  worthy  of 
consideration.  I  will  not  attempt  to  express  an  opinion  as  to 
the  cause  of  their  extinction  in  that  country,  but  it  seems 
to  me  that  it  must  be  due  to  causes  not  yet  understood ;  and 
if  the  profound  thinkers  in  entomological  matters,  of  whom 
England  has  so  many,  have  not  satisfactorily  settled  this 
question,  it  would  be  folly  for  me  to  express  any  decided 
opinion  on  the  subject.  I  wish,  however,  to  call  attention 
to  one  or  two  points.  Great  Britain,  because  of  its  insular 
position,  the  prevailing  winds  and  the  currents  in  the  sur- 
rounding ocean,  has  a  far  different  climate  from  that  of 
Massachusetts  or  the  interior  of  Europe  and  other  parts  of 
the  old  world,  where  this  insect  is  usually  most  abundant. 
I  noticed,  when  in  England,  that  the  foliage  of  all  vegetation 
seemed  darker  than  in  this  country,  or,  at  least,  than  in  the 
eastern  part  of  it ;  and  it  occurred  to  me  that  this  might  be 
due,  in  part,  to  the  larger  amount  of  moisture  in  the  atmos- 
phere, especially  as  quite  similar  conditions  of  climate,  with 
darker  foliage  occur  in  British  Columbia,  as  I  have  been  in- 
formed by  my  colleague,  Mr.  E.  H,  Forbush,  who  also  states 
that  the  arboreal  animals  of  that  region  are  much  darker  than 
those  in  the  eastern  parts  of  the  United  States.  Some  years 
ago,  while  in  England,  my  kind  friend,  Mr.  C.  G.  Barrett, 
gave  me  a  very  complete  series  of  British  Tortricids,  and 
I  never  look  at  my  collection  without  noticing  how  much 
darker  these  insects  are  than  the  same  species  from  Germany 
and  other  parts  of  Europe.  It  seems  to  me  that  this  dark- 
ening may  have  resulted  from  natural  causes,  operating 
through  a  very  long  period  of  years.  When  these  insects 
first  made  their  way  into  the  British  forests  and  fens,  with 
their  darker  surroundings,  the  lighter  colored  individuals, 
contrasting  the  most  with  the  objects  on  which  they  rested, 
naturally  fell  a  prey  to  their  enemies  more  readily  than  the 
dark-colored  individuals  ;  the  darker  ones  were  left  to  propa- 
gate the  species,  and,  in  time,  a  dark  race  was  formed.  I 
am  well  aware  that  I  am  now  trespassing  on  ground  which 
is  far  better  understood  by  my  English  brethren,  but  I  trust 
that  I  may  be  permitted  to  call  attention  to  this  matter  for 


272  THE   GYPSY  MOTH. 

the  purpose  of  considering  the  bearing  of  environment  and 
climate  on  the  gypsy  moth. 

If  we  suppose  that  the  native  home  of  this  insect  was  in 
central  Europe  or  south-western  Asia,  and  that  it  was  de- 
veloped from  some  progenitor  in  which  the  sexes  were  of  the 
same  color,  possibly  not  very  unlike  the  males  of  the  present 
time,  we  may  well  suppose  that,  as  the  females  developed 
a  larger  number  of  eggs,  rendering  them  so  heavy  that  they 
flew  but  rarely,  and,  in  time,  not  at  all,  their  wings,  not  being 
used,  would  grow  weaker  and  less  useful  as  organs  of  flight, 
as  we  now  find  them.  Under  these  circumstances,  suppose 
them  to  be  inhabiting  trees  and  shrubs,  the  bark  of  which  is 
of  light  color,  as  birch,  their  enemies,  the  birds,  etc.,  could 
readily  distinguish  these  strongly  contrasting  females  on  the 
trunks  of  the  trees  and  destroy  the  darker  forms,  leaving 
the  lighter  examples  to  propagate  the  species ;  and,  as  this 
went  on,  in  time  permanently  light-colored  females  would  be 
produced. 

The  males  fly  actively  during  the  day,  and  are  captured, 
while  on  the  wing,  by  insectivorous  birds ;  but  in  this  case 
slight  variations  in  color  would  not  be  apparent  to  the  birds, 
and  no  discrimination  would  be  made  in  favor  of  such  vari- 
ations. For  this  reason  the  males  have  probably  retained 
more  of  their  primitive  color  and  appearance,  while  the 
females  have  made  a  most  remarkable  change;  and,  as  a 
result,  this  insect  furnishes  a  most  striking  illustration  of 
what  is  called  sexual  dimorphism. 

Another  reason  for  thinking  that  the  males  have  changed 
far  less  than  the  females,  and  that  the  changes  made  were 
perhaps  in  a  different  direction,  is  the  fact  that  they  more 
nearly  resemble  the  males  of  allied  species  than  they  do  the 
females  of  their  own.  Compare  Figs.  3  and  4,  on  Plate  I., 
with  Figs.  11,  14  and  17,  on  Plate  39,  and  also  with  Figs.  1 
and  2,  on  Plate  I.  The  three  species  of  Orgyia  just  referred 
to  have  wingless  females  (one  of  which,  O.  leucostigma,  is 
represented  on  Plate  39,  Fig.  18),  which  are  so  heavy  that 
it  would  be  impossible  for  them  to  fly  with  wings  of  ordinary 
size.  It  is  probable,  however,  that  the  remote  ancestors  of 
these  insects  were  winged  in  both  sexes,  and  that,  as  the  female 
developed  a  larger  reproductive  system  and  more  eggs,  she 


INJURIES  IN  THE  OLD  WORLD.  273 

became  too  heavy  for  flight,  and  at  last  abandoned  all  at- 
tempts, just  as  the  gypsy  moth  is  now  doing,  and  that  by  dis- 
use these  organs  became  atrophied,  and  nothing  now  remains 
but  mere  rudiments  of  the  wings.  A  similar  fate  possibly 
awaits  the  gypsy  moth.  Two  of  the  species  of  Orgyia, 
figured  on  Plate  39,  Figs.  14  and  17,  are  so-called  natives 
of  this  country;  while  the  other,  Fig.  11,  is  a  native  of 
Europe,  and  has  been  in  this  country  probably  a  compara- 
tively short  time,  not  long  enough,  at  any  rate,  for  the  new 
environment  to  produce  any  noticeable  change.  Since  the 
introduction  of  O.  deftnita  (Fig.  14)  and  0.  leucostigma  into 
this  country,  whenever  and  in  whatever  way  that  may  have 
happened,  the  three  species  have  been  in  an  environment 
which  has  produced  marked  changes  in  the  males,  while  the 
wingless  females  have  probably  changed  far  less.  The  two 
American  species  have  changed  so  little  from  each  other  that 
O.  definila,  for  a  long  time,  was  not  recognized  as  a  distinct 
species.  It  may  have  branched  off  from  the  stem  of  leucos- 
tigma at  a  comparatively  recent  date. 

If,  in  comparatively  recent  times,  the  gypsy  moth  made  its 
way  into  England,  by  the  help  of  man  or  otherwise,  may  not 
the  darker  color  of  the  foliage  and  other  surroundings  have 
rendered  the  female  moths  more  conspicuous  objects  to  their 
enemies,  so  that,  "  in  the  struggle  for  existence,"  this  species 
was  exterminated  before  it  had  time  to  take  on  the  darker 
colors,  as  may  have  been  the  case  with  the  British  Tortri- 
cids?  It  may  be  thought  that  the  warm,  damp  climate  of 
England  would  favor  fungoid  plants  which  are  destructive  to 
insect  life  ;  but,  if  this  caused  the  extermination  of  the  gypsy 
moth  in  England,  why  has  it  not  also  caused  the  extermi- 
nation of  numerous  other  species  with  more  or  less  similar 
larval  habits?  If  any  of  the  above  conditions  caused  the 
extinction  of  this  moth  in  England,  we  have  little  to  hope 
for  in  America,  since  so  very  little  of  our  territory  has  any 
such  climatic  conditions  as  England. 

INJURIES  IN  THE  OLD  WORLD. 

There  are  many  accounts,  in  the  older  books,  of  extensive 
damage  done  by  insects  at  different  times  in  various  parts 
of  Europe,  some  of  which  was  probably  caused  by  the  gypsy 


274  THE   GYPSY   MOTH. 

moth ;  but  it  is  impossible  to  be  quite  sure  what  insects  may 
have  been  referred  to  in  these  old  accounts  for  the  reason 
that  only  local  common  names  were  used  before  1758,  when 
Linnaeus  introduced  the  custom  of  giving  a  scientific  name 
to  each  insect,  by  which  it  should  be  known  in  all  countries. 

In  a  work  entitled  "  Beschreibung  von  allerlei  Insecten  in 
Teutschland,"  by  J.  L.  Frisch,  published  in  Berlin,  1720, 
Vol.  I,  page  14,  is  a  brief  notice  of  a  garden  and  forest 
caterpillar  which  is  evidently  the  gypsy  moth.  Plate  III 
represents  a  male,  a  female  laying  her  eggs,  a  caterpillar, 
the  anterior  and  posterior  ends  of  a  caterpillar  and  a  male 
antenna.  He  writes  of  this  insect  as  follows:  "This  cat- 
erpillar, in  the  third  part  of  the  copper-plate,  Fig.  1,  is 
called  Bunt-Knopffig,  on  account  of  the  light  violet-blue 
and  purple-red  tubercles  on  its  back,  and  also  Garten  und 
Forstraupe  (garden  and  forest  caterpillar),  because  it  not 
only  destroys  all  the  leaves  of  the  fruit-bearing  trees  of  the 
orchard,  but  also  does  not  hesitate  to  attack  forest  trees, 
especially  the  oaks,  on  which  it  is  found  every  year.  In  this 
year,  1720,  this  caterpillar  entirely  stripped  every  tree  of 
the  double  row  of  lindens  along  the  road  from  Neustadt  to 
Berlin."  In  the  appendix  to  this  work,  published  later,  is  a 
statement  that  a  certain  injurious  caterpillar  (possibly  the 
gypsy  moth),  in  1721  and  1722,  ravaged  not  only  the  fruit 
trees,  throughout  Germany,  but  also  oaks  and  other  forest 
trees,  and  even  killed  many  of  them. 

Thomas  Brown,  in  the  "  Book  of  Butterflies,"  Vol.  II,  page 
52,  published  in  London  in  1832,  states  that  in  1731  the 
caterpillars  of  the  gypsy  moth  committed  terrible  havoc 
among  the  cork  oaks  of  France. 

In  1761,  J.  C.  Schaefier  published  a  work  on  the  gypsy 
moth,  the  first  edition  of  which  appeared  in  1752.  He  states 
that  in  this  last  year  the  trees  in  the  orchards  and  gardens, 
the  bushes  in  the  fields,  and  even  whole  forests,  not  only  in 
many  places  in  Saxony  but  also  in  Altenburg,  Leitz,  Naurn- 
burg,  Sangerhausen  and  many  other  regions,  were  entirely 
stripped  of  their  leaves.  The  branches  and  twigs  were 
densely  covered  with  caterpillars,  instead  of  leaves,  and  they 
also  crawled  over  the  ground  in  great  numbers.  An  exam- 
ination proved  that  they  all  belonged  to  this  one  species,  and 


INJURIES  IN  THE  OLD  WORLD.  275 

that  they  had  been  more  or  less  abundant  for  three  years  in 
succession.  The  first  year  there  were  not  very  many,  the 
second  they  were  comparatively  numerous  and  the  third  year 
they  were  present  in  overwhelming  numbers.  Some  of  the 
common  people  thought  that  the  caterpillars  grew  out  of  the 
ground,  like  the  grass ;  others  thought  that  they  were  cre- 
ated by  the  evil  one  ;  still  others  assured  the  author  that  they 
had  seen  with  their  own  eyes  thousands  of  the  caterpillars 
brought  by  the  wind ;  and,  finally,  there  were  many  who 
thought  these  caterpillars  were  sent  by  God  as  a  punishment 
for  their  sins.  The  author  states  that  about  eleven  years  be- 
fore, he  saw  this  same  species  in  Saxony,  after  having  stripped 
the  leaves  from  every  tree  and  shrub  in  the  vicinity,  feed  on 
grass  and  grain. 

In  the  "  Naturforscher,"  Vol.  XVI,  page  130,  1781,  Pas- 
tor C.  J.  Rimrod  gave  a  long  and  very  good  account  of  the 
gypsy  moth,  and  wrote  of  two  invasions  at  his  home  in  Quen- 
stedt,  one  in  1760-61  and  the  other  in  1781. 

Preyssler,  as  stated  by  Bechstein,  in  his  "  Vollstandige 
Naturgeschichte  der  schadlichen  Forstinsekten,"  page  372, 
1804,  says  that  the  gypsy  moth  was  once  very  common  at 
Prague,  and  stripped  the  leaves  from  the  fruit  trees,  so  that 
they  bore  no  fruit.  Bechstein,  in  the  same  place,  says  that 
this  is  a  formidable  insect,  against  which  very  active  meas- 
ures must  be  taken,  for,  because  of  its  large  brood  and  great 
voracity,  the  damage  done  by  the  caterpillars  may  be  easily 
understood.  Linnaeus  and  Fabricius  call  it  the  pest  of  the 
fruit  garden. 

Panzer,  in  his  "  Faunae  Insectorum  Germanicae,"  Vol.  II, 
page  22, 1794,  says  the  caterpillars  of  this  insect  appeared  for 
many  years  in  frightful  numbers,  and  destroyed  the  fruit  trees 
to  the  great  injury  of  their  owners.  In  1818,  the  cork-oak 
forests  extending  from  Barbaste  to  Podenas,  in  south-western 
France,  were  devastated  by  innumerable  hosts  of  gypsy  moth 
caterpillars.  After  having  devoured  both  the  leaves  and  the 
acorns,  they  attacked  the  maize,  millet,  fodder  and  all  the 
fruits.  They  even  invaded  the  dwellings  in  the  neighborhood 
of  the  trees,  to  the  extreme  annoyance  of  the  occupants. 

Godart  says,  in  his  "  Iconographie  des  Chenilles,  Les  Bom- 
by cites," published  in  1832  :  "This  caterpillar  lives  on  nearly 


276  THE   GYPSY  MOTH. 

every  species  of  tree,  and,  as  it  is  as  common  as  voracious, 
it  often  causes  great  damage  to  orchards  of  fruit  trees  as  well 
as  in  the  parks  and  forests,  and,  together  with  other  cater- 
pillars, often  completely  defoliates  them."  This  same  author, 
in  his  "Histoire  Naturelle,"  Vol.  IV,  page  256,  states  that  in 
1823  the  trees  in  the  forest  of  Senart  in  Fontainebleau  were 
entirely  defoliated  by  the  gypsy  moth,  so  that  the  trees  were 
as  bare  as  in  winter.  Finding  nothing  further  to  devour, 
the  caterpillars  crawled  over  the  ground  in  all  directions, 
seeking  food.  M.  Daudeville,  writing  in  the  "Annales  de 
la  Societe  d'Horticulture  de  Paris,"  Vol.  Ill,  page  98,  1828, 
after  referring  to  this  caterpillar  and  the  descriptions  that 
had  been  given  of  it,  said  that  the  pest  extended  from  the 
west  to  the  north-east  of  the  city  of  Saint  Quentin,  for  a 
distance  of  more  than  sixty  miles,  and  had  completely  dev- 
astated the  trees,  so  that  they  were  entirely  bare.  These 
insatiable  insects  not  only  devoured  the  buds,  leaves  and 
flowers,  but  even  the  small  twigs  of  fruit  trees.  For  three 
years,  in  an  orchard  of  three  hundred  apple  trees,  they  had 
not  left  a  leaf  intact,  and  the  gradual  decay  and  death  of 
several  of  the  trees  were  attributed  to  these  insects.  In  the 
same  journal  it  was  stated  that  Viscount  Hericart  of  Thury, 
in  a  journey  which  he  had  just  completed,  observed  that  the 
apple  trees  in  the  departments  of  Calvados,  the  Eure,  Eure- 
et-Loir,  the  Seine-Inferieur,  Seine-et-Oise,  the  Oise,  the 
Somme  and  the  Aisne  were  entirely  ravaged  by  this  insect. 
Mons.  N.  Joly,  in  the  "  Revue  Zoologique,"  Vol.  V,  page 
115,  1842,  says  that  during  the  years  1837, 1838  and  1839, 
there  appeared  in  the  forests  around  Toulouse  in  France  an 
innumerable  quantity  of  the  gypsy  moth.  The  caterpillars 
of  this  insect  attacked  the  oaks  with  such  avidity  as  to 
strip  them  completely  of  their  foliage,  so  that  after  the  first 
onslaught  the  trees  appeared  as  they  do  in  winter.  The 
caterpillars  were  so  numerous  that  persons  passing  through 
the  woods  could  hear  them  eating,  and  might  easily  believe 
themselves  in  the  midst  of  a  menagerie.  These  devastating 
insects  occupied  an  area  of  more  than  twenty-five  square 
leagues.*  On  their  approach  to  Toulouse  they  attacked 

*  An  area  nearly  as  large  as  the  infested  territory  in  Massachusetts. 


INJURIES  IN  THE   OLD   WORLD.  277 

the  willows,  which  they  damaged  much  less,  because  of  the 
ability  this  tree  possesses  of  putting  on  new  foliage.  In 
the  "  Stettiner  Entomologische  Zeitung,"  Vol.  IX,  page  266, 
1848,  it  is  stated  that  Riegel  in  1838  saw  about  eight  acres 
of  oak  woods  entirely  stripped  of  leaves  by  the  gypsy  moth. 
Ratzeburg,  in  "Die  Waldverderbniss,"  published  in  1868, 
Vol.  II,  page  154,  says  the  gypsy  moth,  ten  years  before, 
had  spread,  in  a  space  of  three  years,  from  Brandenburg  to 
the  zoological  gardens.  On  page  189  he  says  that  the  size 
and  voracity  of  this  caterpillar  (gypsy  moth)  and  the  vast 
numbers  in  which  they  sometimes  appear  make  the  results 
for  the  beech,  as  well  as  for  the  elm,  frightful  in  the  extreme. 
In  the  zoological  gardens  at  Berlin  the  beeches  are  said  to 
have  been  severely  attacked.  A  very  competent  observer, 
Dr.  Gerstacker,  as  an  eye-witness,  stated  that  in  1852  many 
beeches  became  dry  and  dead.  In  that  year  all  the  cater- 
pillars transformed,  but  in  1853,  not  having  sufficient  food, 
many  died  of  starvation.  On  page  339,  in  speaking  of  the 
ravages  of  different  species  of  caterpillars,  he  says  that 
Bombyx  dispar  (the  gypsy  moth)  may  be  mentioned  first  as 
being  the  largest  and  most  ravenous,  and  further  says  that 
he  knew  of  a  devastation  by  which  was  caused  the  weakening 
and  death  of  many  trees.  This  author  states  (page  185)  that 
in  the  great  devastation  which  occurred  in  the  zoological 
gardens  at  Berlin,  in  1851-53,  these  caterpillars  attacked 
not  only  the  native  but  also  the  foreign  trees  and  shrubs 
cultivated  there,  no  species  being  entirely  avoided  by  them. 

Bazin,  in  an  article  on  "The  Ravages  upon  the  Oaks  by 
Bombyx  dispar"  published  in  "Bulletin  de  la  Societ6  des 
Sciences  historiques  et  naturelles  de  1'Yonne,"  pages  11-20, 
1870,  speaks  of  the  abundance  of  this  species  everywhere. 
Before  the  middle  of  June,  1868,  "there  were  spots  in  the 
woods  that  every  day  spread  like  spots  of  oil  on  the  water, 
where  not  a  leaf  remained  on  the  trees  or  shrubs."  The  oaks 
were  attacked  first,  and  after  they  had  been  stripped  the 
birches,  aspens,  elms  and  even  pines  and  larches  were  com- 
pletely denuded.  In  the  fields  a  large  number  of  apple  trees 
were  defoliated  by  this  caterpillar,  and  the  apples  themselves 
were  sometimes  eaten  into  to  such  an  extent  that  they  became 
malformed.  In  the  same  article  M.  Bazin  states  that  it  was 


278  THE  GYPSY  MOTH. 

reported  that  caterpillars  of  this  species  had  occasioned  the 
death  of  children  who  had  eaten  strawberries  upon  which 
these  caterpillars  had  rested,  and  that,  as  a  consequence,  the 
sale  of  strawberries  had  been  prohibited  in  certain  regions. 
It  did  not  seem  possible  that  the  story  of  the  death  of  the 
children  from  this  cause  could  be  true,  or  even  that  any 
derangement  of  the  digestive  system  could  have  occurred. 
To  test  the  statement,  M.  Bazin  put  four  gypsy  moth  cater- 
pillars in  a  wide-mouthed  bottle  with  twelve  strawberries 
and  a  strawberry  leaf.  At  the  end  of  twenty-four  hours  they 
had  eaten  a  very  little  of  the  leaf  and  also  a  little  of  the 
strawberries,  but  had  not  eaten  them  with  the  avidity  that 
they  do  other  kinds  of  food.  They  had  been  in  contact  with 
the  strawberries  more  completely,  however,  than  they  would 
if  they  had  been  at  liberty,  for  they  had  crawled  over  the 
berries  again  and  again,  and,  if  they  had  the  power  to  impart 
to  them  any  injurious  properties  by  contact,  they  must  have 
done  so  under  these  conditions.  M.  Bazin  then  ate  four  of 
these  strawberries,  and,  a  little  later,  feeling  no  inconvenience 
from  these,  ate  the  remaining  eight,  without  the  slightest 
disturbance  in  the  stomach.  As  the  opinion  prevailed  more 
or  less  widely  that  cows  and  other  animals  that  had  eaten 
these  caterpillars  had  been  made  sick,  he  caused  a  dog  to 
swallow  some  of  them,  but  the  animal  gave  no  indication  of 
inconvenience. 

In  reviewing  Dr.  E.  L.  Taschenberg's  "Entomologie  fiir 
Gartner,"  etc.,  in  the  "  Stettiner  Entomologische  Zeitung," 
Vol.  XXXII,  page  167,  1871,  Dr.  Dohrn,  in  speaking  of 
the  gypsy  moth,  says  that  from  his  experience  the  active 
caterpillars,  after  escaping  from  the  eggs,  can  crawl  about 
for  eight  or  ten  days  without  food.  He  states  that  on  May 
3,  1854,  he  was  in  Glogau,  and  noticed  gypsy  moth  cater- 
pillars crawling  on  his  own  clothing  as  well  as  on  that  of 
others.  Under  the  roof  of  the  shed,  near  which  they  sat, 
thousands  of  caterpillars  which  had  hatched  that  day  were 
crawling  about.  They  had  let  themselves  down  by  threads, 
and  thus  dropped  upon  the  clothes  of  the  people.  Threads 
from  many  more  caterpillars  had  become  entangled  into  long 
chains,  which  waved  in  the  almost  imperceptible  breeze,  and 
from  which  hung,  so  far  as  he  could  judge,  about  a  thousand 


INJURIES  IN  THE  OLD  WORLD.  279 

caterpillars.  In  another  village  he  saw,  some  time  later  on 
a  fine  day,  caterpillars  of  this  same  species  swaying  on  long 
threads  from  apple  trees  in  an  orchard,  and  which,  although 
there  was  no  wind,  were  directed  towards  a  neighboring 
orchard  which  the  owner  had  always  kept  carefully  cleared 
of  caterpillars  and  egg-clusters,  and  who  had  often  com- 
plained of  the  laziness  and  ill-will  of  his  neighbor.  On  the 
highway  in  Herms  village,  in  Glogau,  the  same  summer,  a 
large  apple  tree  was  eaten  almost  bare  of  leaves,  and  the  fe- 
male moths  were  laying  their  eggs  on  the  trunk.  Later  in  the 
season  Dohrn  states  that  he  saw  the  tenant  carefully  scrap- 
ing off  the  egg-clusters,  even  from  the  highest  branches,  and 
he  expected  the  tree  would  be  quite  free  from  these  caterpil- 
lars the  next  year ;  but  to  his  astonishment,  in  the  following 
July,  it  was  full  of  gypsy  moth  caterpillars,  and  eaten  bare. 
The  tenant  said  he  would  do  nothing  more  in  future,  since 
all  his  work  was  of  no  avail ;  but,  upon  questioning  him  as 
to  whether  he  had  burned  the  eggs,  he  replied  that  such  a 
thing  had  not  occurred  to  him.  He  had  simply  trodden  all 
the  egg-clusters  and  scrapings  into  the  ground,  where  they 
had  been  preserved,  and  the  caterpillars,  hatching  out  the  fol- 
lowing year,  found  their  way  up  into  the  tree. 

In  an  article  in  the  "  Bullettino  della  Societa  Entomologica 
Italiana,"  Vol.  Ill,  page  360,  1871,  published  in  Florence, 
Italy,  Apelle  Dei  has  an  article  on  the  "Ravages  of  Insects 
in  the  Senesian  Country,"  in  which  he  mentions  the  gypsy 
moth,  stating  that  it  had  ravaged  the  oak  forests  of  the  high 
Chianti  for  many  years,  and  during  the  year  1871  they  had 
stripped  the  forests  of  Chianti  to  an  extent  and  with  a  sever- 
ity that  was  frightful,  and  that  many  of  the  oaks  had  been 
destroyed.  Dubois,  in  his  "  Lepidopteres  de  Belgique," 
Vol.  II,  published  in  Brussels  in  1874,  states  that  in  1858, 
Brussels  and  its  neighborhood  suffered  very  much  from  the 
ravages  of  the  gypsy  moth,  notably  the  boulevards  and  park. 

Porchinsky,  in  his  work  on  "Insects  Injurious  to  Fruit 
Gardens  in  the  Crimea,  Russia,"  published  in  St.  Petersburg 
in  1889,  states  that  the  gypsy  moth  caterpillar  appears  in  the 
Crimea  not  unfrequently  in  enormous  quantities.  This  hap- 
pened in  1842,  and  also  in  the  early  sixties  and  seventies. 
Especially  during  1871  were  the  gardens  of  the  Crimea  nearly 


280  THE   GYPSY  MOTH. 

destroyed.  In  1884  these  caterpillars  were  so  numerous  that 
they  covered  the  railroad  tracks  so  that  trains  were  moved 
with  difficulty.  Again,  in  1885,  they  occurred  in  great  num- 
bers along  the  southern  shore.  Observations  in  the  Crimea 
show,  however,  that  the  gypsy  moth  rarely  continues  in  the 
same  locality  in  large  quantities  for  more  than  three  years. 
Thus  in  1861,  an  unusually  large  number  of  caterpillars  was 
noticed  in  the  Crimea,  and  they  continued  to  increase  until 
1863,  when  their  highest  number  was  reached.  Although 
the  greater  part  of  the  caterpillars  succeeded  in  forming 
cocoons,  yet  very  many  of  them  were  diseased,  as  was  shown 
by  their  soft  and  withered  condition,  and,  when  broken  open, 
there  flowed  out  from  some  of  them  a  dark-brown  liquid 
mass.  In  1864,  there  were  decidedly  less  caterpillars  than 
during  the  previous  year,  while  only  occasional  individuals 
were  met  with  in  1865. 

In  a  work  on  "  Insects  Injurious  to  Gardens  and  Orchards 
in  Central  and  Northern  Russia,"  by  N.  Kulagin  of  the  Uni- 
versity of  Moscow,  published  in  St.  Petersburg  in  1894,  it 
is  stated  that  the  gypsy  moth  is  very  widely  distributed.  It 
is  found  in  all  the  central  provinces  of  Eussia,  in  the  Cauca- 
sus and  in  southern  Siberia.  Besides  injuring  fruit  trees, 
the  caterpillars  destroyed  the  leaves  of  forest  trees  over  an 
extent  of  territory  comprising  from  one  thousand  to  three 
thousand  dessatines  (2,860  to  8,580  acres). 

In  a  work  on  "Injurious  Insects,"  by  Theodore  Keppen, 
published  in  Eussia  in  1883,  Vol.  Ill,  commencing  on  page 
49,  it  is  stated,  in  speaking  of  the  gypsy  moth,  that  these 
caterpillars  often  appear  in  countless  numbers.  In  1852,  in 
the  vicinity  of  Kishenev,  eighty-three  miles  north-west  of 
Odessa,  they  occurred  by  millions  in  the  gardens  and  forests. 
Having  destroyed  all  the  leaves,  they  attacked  the  bark 
of  the  young  shoots  and  completely  ruined  a  large  number 
of  different  kinds  of  trees.  In  1842,  and  also  in  the  early 
sixties  and  seventies,  Georg  Seopru  states  that  they  were 
exceedingly  injurious  to  the  fruit  trees  in  the  Crimea.  Ac- 
cording to  the  statements  of  Professor  Eversmann,  the  for- 
ests of  oak  and  aspen,  in  the  province  of  Orenboorg,  were 
stripped  of  their  leaves,  presenting  the  same  appearance 
as  in  winter.  In  1852,  the  caterpillars  laid  waste  the  forests 


EXPLANATION  OF  PLATE  40. 


Drawn  in  colors  by  ELLA  M.  PALMER. 


1.  Showing  the  feeding  and  spinning  habits  of  gypsy  moth    cat- 

erpillars of  different  ages.  The  bark  on  the  lower  part 
of  the  apple  twig  has  been  eaten  by  the  young  cater- 
pillars early  in  the  season. 

2.  Showing  the  method  of  feeding  upon  a  young  growing  shoot 

of  white  pine   (Pinus  strobus} . 

3.  Red    oak    {Quercus   rubra)    leaf  attacked    by   a    nearly    full- 

grown  gypsy  moth  caterpillar. 


FEEDING  HABITS  OFGYPSY  MOTH  CATERPILLARS. 


INJURIES   IN  THE  OLD   WORLD.  281 

of  oak,  linden  and  beech  in  the  province  of  Kazan,  but  sub- 
sequently these  trees  put  out  a  new  set  of  leaves. 

The  late  V.  E.  Graff  reported  that  the  oak  suffered  greatly 
in  the  province  of  Yekaterin.  In  1856,  the  gypsy  moth  was 
observed  in  great  abundance  in  the  province  of  Riazan.  In 
1857,  the  forests  near  the  province  of  Tambov  were  visited 
by  vast  masses  of  these  caterpillars.  The  trunks  of  the  wild 
apple  and  cherry  trees  were  wrapped  about  with  a  felt-like 
substance  formed  by  the  covering  of  the  eggs.  During  1863, 
these  caterpillars  were  seen  in  vast  numbers  on  the  oak  in 
various  forests  in  the  province  of  Kazan.  Here,  as  stated 
by  Tideman,  the  trees  injured  most  were  the  oak,  linden, 
maple,  elm  and  birch,  while  the  mountain-ash  and  hazel-nut 
did  not  suffer  so  much.  In  1867,  the  caterpillars  were  seen 
in  other  districts,  and  in  1868,  their  numbers  became  fright- 
ful to  contemplate  throughout  the  whole  province  of  Kazan. 
In  1867  to  1869,  the  gypsy  moth  caterpillars  were  very  de- 
structive in  the  province  of  Samara,  and  Rudzky  states  that 
they  were  very  abundant  at  the  same  time  in  all  parts  of  the 
province  of  Penza.  During  June,  1867,  all  the  trees  on 
many  estates  were  entirely  stripped  of  their  leaves,  and  the 
forests  in  many  cases  to  the  extent  of  several  hundred  des- 
satines  *  appeared  as  they  do  in  the  winter.  The  caterpillars 
seemed  to  prefer  the  oak  and  linden,  but  after  defoliating 
these  they  attacked  other  trees  and  shrubs,  and  finally  de- 
stroyed the  grass.  In  the  forests  near  the  city  of  Penza  the 
dead  caterpillars  formed  such  putrid  masses  that  the  police 
were  obliged  to  take  measures  to  destroy  the  decaying  heaps. 
An  incalculable  quantity  of  eggs  were  laid  on  the  trunks  of 
both  deciduous  and  evergreen  trees.  In  1869  and  1871,  the 
gypsy  moth  caterpillars  appeared  in  great  quantities  in  the 
Kupiansk  district  of  the  province  of  Kharkov. 

In  more  recent  times,  1879-80,  these  caterpillars  multiplied 
in  frightful  numbers  and  spread  over  an  immense  territory, 
beginning  in  the  province  of  Kiev  and  Poltava  and  extend- 
ing through  Kharkov,  Voronezh,  Tambov,  Saratov,  Sim- 
beersk  into  Kazan,  f  Owing  to  defective  reports  concerning 

*  One  dessatine  is  equal  to  2.86  acres. 

t  A  territory  about  equal  to  all  our  Atlantic  States,  and  in  nearly  the  same  lati- 
tude as  Labrador. 


282  THE  GYPSY  MOTH. 

this  unusual  appearance  of  Porthetria  dispar,  it  is  hard  to 
say  where  the  calamity  began.  Considering  the  time  of  their 
appearance,  it  is  supposed  that  they  first  appeared  en  masse 
in  the  province  of  Kharkov.  According  to  Yaroschev,  the 
caterpillars  were  seen  in  threatening  numbers  in  the  district 
of  Zmiev  during  1877-78.  The  insect  may  have  spread 
westward  in  the  province  of  Poltava  and  eastward  in  the 
province  of  Voronezh,  and  from  these  to  more  distant  parts. 
The  simultaneous  appearance  in  different  places  so  widely 
separated,  led  to  the  opinion  that  there  were  various  places 
of  origin  from  which  the  insect  was  distributed.  Yaroschev 
states  that  the  caterpillars  were  so  abundant  in  the  vicinity 
of  Zmiev,  in  1878,  that  in  going  from  one  forest  to  another 
they  literally  covered  the  walls  of  the  houses  lying  in  the 
way.  They  fed  on  all  sorts  of  plants,  except  ash  (Fraxmus 
excelsior)  and  wild  pear. 

Anderson  gives  interesting  details  of  the  presence  of  the 
caterpillars  in  the  forest  of  Shipov  in  the  province  of  Voro- 
nezh. They  first  attacked  the  so-called  winter  oaks  (  Quer- 
cus  pedunculata,  var.  tardiflora),  and,  after  destroying  the 
leaves  as  soon  as  they  appeared,  they  devoured  the  leaves  of 
the  lime  tree,  aspen,  hawthorn,  spindle  tree,  hazel  and  others, 
and  finally  the  numerous  grasses  were  destroyed.  Early  in 
June  they  began  to  pupate,  and  by  the  middle  of  the  month 
they  were  all  in  this  stage.  About  3,500  dessatines  (10,010 
acres)  of  the  forest  were  laid  bare,  and  detached  trees  in 
other  parts  of  the  woods  were  stripped  of  their  leaves.  By 
the  middle  of  July  the  moths  had  emerged  and  laid  an  enor- 
mous number  of  eggs. 

According  to  Gazen,  vast  quantities  of  these  caterpillars 
were  seen  in  the  district  of  Kirsanov  in  the  province  of  Tam- 
bov, in  April,  1879.  Having  eaten  all  the  leaves  on  the  trees 
and  shrubs,  the  caterpillars  descended  to  the  ground  and  lit- 
erally covered  it  in  all  directions.  In  the  district  of  Volsk, 
in  the  province  of  Saratov,  the  caterpillars  of  the  gypsy  moth 
appeared  in  vast  numbers  in  April,  1879,  eating  the  leaves 
of  all  sorts  of  trees,  though  preferring  the  birch  and  oak, 
and  finally  they  attacked  the  pine.  By  the  end  of  May, 
10,000  dessatines  (28,600  acres)  of  forest  were  completely 
denuded  of  their  leaves.  After  this  they  devoured  the 


INJURIES  IN  THE  OLD  WORLD.  283 

grass,  and,  coming  to  a  field  of  grain  in  their  march,  they 
destroyed  that  also.  In  1880,  they  appeared  in  force  in  the 
forests  of  the  provinces  of  Simbeersk  and  Kazan. 

In  a  letter  from  Professor  Henry  of  the  School  of  For- 
estry, Nancy,  France,  dated  July  27, 1895,  he  says  :  i(Liparis 
dispar  (the  gypsy  moth)  is  well  known  to  French  foresters. 
This  caterpillar  is  a  plague  to  fruit  trees,  oaks,  chestnuts, 
lindens,  elms,  poplars  and  other  trees,  on  all  of  which  it 
thrives.  In  1868,  more  than  60  hectares  (148|  acres)  of  oak 
woods  were  entirely  stripped  by  it.  It  was  so  common  in 
1880,  on  the  sides  of  Mt.  Ventoux  near  Avignon,  that  the 
legions  of  caterpillars  covered  the  ground  and  entirely  de- 
stroyed vegetation.  In  Savoy  it  made  an  invasion  in  1887 
upon  the  chestnuts  and  fruit  trees.  There  is  not  a  year 
passes,  comparatively  speaking,  in  which  the  caterpillars  do 
not  show  themselves  in  our  territory,  if  not  in  one  place 
then  in  another."  In  a  letter  from  Dr.  J.  Ritzema-Boz,  from 
Amsterdam,  Sept.  3,  1895,  he  writes  that  this  insect  is  com- 
mon in  Holland  and  also  in  all  western  Europe,  but  the 
ravages  of  the  caterpillar  are  very  much  more  common  in 
the  eastern  parts  of  Europe.  In  Holland  the  ravages  of  the 
gypsy  moth  are  very  rare  indeed.  In  1848,  it  stripped  the 
leaves  from  the  oak  (  Quercus  pedunculata)  over  50  hectares 
(123^7g  acres)  near  Lutphen  in  the  Dutch  province  of  Gelder- 
land,  and  then  attacked  the  other  trees.  In  1887  it  was  very 
abundant  on  oak  near  Wymegen  in  the  province  of  Gelder- 
land.  In  1880  these  caterpillars  destroyed  the  leaves  on  a 
large  number  of  hectares  of  oaks  near  Veenendeal  in  the 
province  of  Utrecht. 

In  a  letter  from  N.  Nasonov,  of  the  University  Museum  of 
Zoology,  in  Warsaw,  Poland,  dated  Aug.  7,  1895,  he  writes 
that  he  had  the  opportunity  of  knowing  personally  of  an 
immense  number  of  the  caterpillars  of  the  gypsy  moth  in 
the  orchards  of  the  government  of  Warsaw  during  the  years 
1891  and  1892,  and  also  on  the  deciduous  trees  in  the 
government  of  Moscow  in  1894.  In  1892,  the  leaves  of 
the  fruit  trees  in  Warsaw  were  eaten  by  these  caterpillars 
to  such  an  extent  that  they  bore  no  fruit.  According  to 
the  information  received  from  the  central  Russian  govern- 
ment, the  caterpillars  of  the  gypsy  moth  have  this  summer 


284  THE  GYPSY  MOTH. 

(1895)  nearly  defoliated  the  forests  in  the  government  of 
Kalonga. 

Notwithstanding  the  general  damage  to  all  kinds  of  vege- 
tation in  Europe,  the  greatest  complaint  comes  from  the 
fruit-growing  districts,  where  this  insect  shows  a  preference 
for  the  foliage  of  fruit  trees. 

METHODS   OF  DESTROYING  THE  GYPSY  MOTH  ix  EUROPE. 

The  natural  enemies  of  the  gypsy  moth,  as  the  birds, 
parasites  and  predaceous  insects,  are  relied  upon  to  a  great 
extent  to  keep  it  in  check  in  European  countries,  except  in 
localities  where  it  is  very  abundant,  and  the  outbreaks  very 
frequent.  It  should  be  borne  in  mind  that  the  European 
methods  are  not  for  the  purpose  of  exterminating  or  even 
preventing  the  spread  of  this  insect;  for,  as  has  already 
been  stated,  it  is  more  or  less  common  everywhere.  The 
extermination  of  this  pest  in  Europe  by  artificial  means 
would  probably  be  an  absolute  impossibility,  and,  therefore, 
all  that  is  attempted  is  to  destroy  it  wherever  it  appears  in 
great  abundance. 

The  usual  methods  are  to  scrape  off  the  egg-clusters  and 
burn  them,  or  cover  them  over  with  raupenleim  or  other 
materials  in  the  fall,  winter  or  spring  before  they  hatch, 
applying  the  substance  by  means  of  a  brush  on  a  long 
pole  to  those  egg-clusters  that  are  too  far  above  the  ground 
to  be  reached  in  any  other  way.  Later  in  the  season  the 
trees  are  protected  from  those  caterpillars  that  hatch  from 
egg-clusters  laid  on  the  ground  or  elsewhere,  by  banding 
with  raupenleim.  The  caterpillars  are  destroyed  whenever 
found,  generally  by  crushing  them  as  soon  as  they  hatch, 
and  while  they  are  still  clustering  on  the  egg-mass,  form- 
ing the  so-called  "  spiegel."  The  pupae  are  destroyed  by 
hand,  and  also  the  female  moths  before  they  have  laid  their 

eggs. 

Dr.  N.  Nasoriov,  of  the  Warsaw  University  Museum  of 
Zoology,  in  the  letter  previously  cited,  writes  that,  in  Po- 
land, the  principal  measures  used  in  combating  these  in- 
sects are  to  destroy  the  eggs,  band  the  trunk  of  the  trees 
with  raupenleim  and  gather  the  caterpillars  and  pupse  by 


REMEDIES   IN  EUROPE.  285 

hand.  In  a  Russian  work  *  by  A.  F.  Rudzky,  is  given  the 
following  :  < « The  eggs  are  laid  on  the  trunks  of  the  trees  in 
large  masses.  These  may  be  easily  scraped  off  with  a  knife 
during  ten  entire  months  in  southern  Russia.  If  the  egg- 
clusters  are  not  scraped  off,  it  is  necessary  to  destroy  the 
caterpillars  as  soon  as  hatched,  and  while  still  clustering  in 
groups.  When  the  caterpillars  have  spread  over  the  whole 
tree,  it  is  as  impossible  to  destroy  them  as  the  separate 
moths.  When  they  have  eaten  the  foliage  from  one  tree, 
they  go  in  a  mass  to  another ;  but  this  may  be,  in  a  measure, 
prevented  by  putting  the  so-called  *  catch  bands '  on  the  tree 
trunks.  The  cheapest  of  these  bands  are  made  of  wadding, 
five  or  six  inches  in  width,  and  bound  on  tightly,  leaving  an. 
upper  and  lower  edge,  which  is  to  be  roughed  up,  so  that 
the  caterpillars  may  become  entangled  in  the  uneven  sur- 
faces. The  wadding  may  be  made  fast  to  the  trunks  with 
strings,  or  glued  together  in  bands.  Where  a  large  number 
of  these  bands  are  needed,  it  is  advisable  to  paste  the  wad- 
ding (during  the  winter)  on  coarse  paper,  one  side  of  which 
is  smeared  with  tar.  Bands  of  pitch  or  tar  are  frequently 
used,  but  these  soon  become  dry.  In  the  Crimea,  a  mixture 
of  two  parts  of  boiled  tar  and  one  part  of  rape  oil,  thoroughly 
heated  together,  is  used ;  also  a  mixture  of  ten  pounds  of 
lard,  twenty  pounds  of  hemp-seed  oil  and  eighty  pounds 
of  coal  tar.  This  is  applied  directly  to  the  tree  and  needs 
renewing  twice  a  year.  Labodsky  recommends  this  same 
ointment,  and  says  that,  when  well  prepared,  it  will  retain 
its  sticky  qualities  an  entire  autumn." 

Theodore  Beling,  inspector  of  forests  at  Seesen,  wrote 
July  21,  1895,  that  the  methods  adopted  there  were  to  kill 
the  caterpillars,  pupae  and  moths,  but  that  the  most  impor- 
tant method  was  to  destroy  the  egg-masses  on  the  tree  trunks 
by  scraping  them  off  and  burning  them,  or  by  covering  them 
with  raupenleim,  or  with  a  mixture  of  four  parts  of  wood 
tar  and  one  part  of  petroleum.  Dr.  Richard  Hess,  in  "Der 
Forstschutz,"  published  in  Leipzig,  1887  and  1890,  gives 
the  following  concerning  the  gypsy  moth:  "Prevention: 
Protection  of  its  enemies,  bats,  cuckoos,  starlings,  crows, 

*  "  Insects  Useful  and  Injurious  to  Fruit  Trees." 


286  THE  GYPSY  MOTH. 

titmice,  tree-creepers,  etc.,  ichneumons  and  tachinids  are 
especially  to  be  noted.  Orchard  trees  should  be  smeared 
with  a  thin  mixture  of  lime,  black-soap,  potash  and  cow- 
dung.  Killing  :  Destruction  of  the  egg-masses,  from  August 
to  April,  by  scraping  them  off  and  burning  them,  or  by 
smearing  them  with  wood-tar  thinned  with  petroleum  or 
raupenleim.  Killing  the  *  spiegel '  in  May,  and  crushing  the 
caterpillars  when  clustering  on  the  trunks  and  branches  of 
the  trees,  from  the  end  of  May  through  June ;  gathering  the 
pupae  in  July  and  August."  In  a  letter  from  Dr.  Ebermayer, 
professor  in  the  University  of  Munich,  dated  July  22,  1895, 
substantially  the  same  methods  are  recommended. 

J.  Porchinsky,  in  his  work  on  "Insects  Injurious  to  Fruit 
'Gardens  in  the  Crimea,"  says:  "The  eggs  should  be  de- 
stroyed in  the  winter  season,  when  time  and  circumstances 
permit.  The  egg-clusters  should  not  be  crushed,  as  this 
might  allow  some  of  them  to  escape ;  but  they  should  be 
carefully  scraped  off  and  burned.  The  eggs  having  been 
destroyed,  the  tree  should  be  protected  from  caterpillars  that 
might  come  from  neighboring  trees  by  'catch  bands'  (pre- 
ventive bands) .  These  preventive  bands  are  almost  the  only 
means  with  which  to  combat  insects  of  all  classes  most  injuri- 
ous to  orchards ;  and,  therefore,  their  consideration  is  of  the 
first  importance ;  but  it  is  not  so  easy  to  find  a  paste  that 
will,  under  all  conditions  of  weather,  retain  the  peculiar 
qualities  desired.  The  most  simple  of  these  *  catch  bands ' 
is  a  belt  of  tar  put  around  the  trunk  of  the  trees,  on  thick 
paper,  smeared  with  tar  and  made  fast  to  the  trunks. 

"In  the  Crimea,  axle  grease  is  placed  about  the  tree 
trunks  in  belts  from  three  and  a  half  to  seven  inches  in 
width,  and  about  twenty-eight  inches  above  the  level  of  the 
ground.  This  ointment  often  retains  its  sticky  qualities  a 
long  time,  yet  it  is  far  from  satisfactory. 

"  The  experiments  of  Klausen,  in  which  he  used  wadding 
as  a  catch  band,  are  of  importance  in  connection  with  the 
question  of  prevention.  A  large  number  of  these  bands  of 
cotton  were  put  around  the  trunks  of  trees,  the  upper  and 
lower  borders  being  well  spread  out,  for,  the  more  fluffy  and 
open  the  cotton,  the  more  easily  the  caterpillars  become 
entangled.  In  the  course  of  two  hours  a  large  number  of 


REMEDIES  IN  EUROPE.  287 

caterpillars  became  entangled,  and  by  evening  were  dead. 
After  a  rain  these  bands  should  be  replaced." 

By  the  advice  of  Prof.  B.  E.  Fernow,  of  the  Department 
of  Agriculture,  Washington,  D.  C.,  I  wrote  the  following 
letter  to  Professor  Altum:  — 

AMHBRST,  MASS.,  U.  S.  A.,  Jan.  21,  1895. 
Prof.  Dr.  BERNARD  ALTUM. 

DEAR  SIR  :  —  I  send  you  by  post  some  papers  which  contain  an 
account  of  the  introduction  and  spread  of  the  "  Schwaminspinner" 
(Ocneria  dispar  L.)  in  this  country,  and  of  the  efforts  that  have 
been  made  to  exterminate  this  insect.  You  will  see  by  an  exam- 
ination of  these  papers  that  the  insect  has  proved  more  destructive 
here  than  it  usually  does  in  Europe,  while  in  England  it  has  be- 
come extinct  from  unknown  natural  causes. 

We  have  already  found  several  parasitic  and  pvedaceous  insects 
preying  on  0.  dispar,  as  you  will  see  mentioned  in  the  reports 
which  I  send  to  you ;  but  I  very  much  wish  to  learn  whether  you 
think  it  would  be  wise  for  us  to  attempt  to  introduce  the  European 
parasites  into  this  country  ;  and,  if  so,  what  parasites  would  it  be 
desirable  for  us  to  introduce,  and  where  and  how  can  they  be  best 
obtained  ?  We  have  been  advised  to  introduce  some  of  the  Euro- 
pean predaceous  beetles,  as  Calosoma  sycophanta  (L.),  Calosoma 
inquisitor  (L.)  and  Silpha  quadripunctata  L.  Others  have  told 
us  that  Calosoma  sycophanta  is  so  large  and  conspicuous  that 
insectivorous  birds  would  destroy  it  to  such  an  extent  that  it  would 
prove  of  little  assistance  in  destroying  the  "  Schwammspinner." 
Will  you  be  so  kind  as  to  give  me  your  advice  on  this  subject,  and 
also  any  information  you  may  have  of  the  methods  used  in  Europe 
for  the  destruction  of  this  insect?  I  have  your  valuable  work  on 
"  Forstzoologie,"  but  from  all  I  can  learn  this  insect  is  more 
troublesome  and  destructive  in  southern  Europe  than  in  Germany. 
I  shall  be  very  grateful  for  any  information  that  you  may  be  able 
to  give  me. 

Very  respectfully,  your  obedient  servant, 

C.  H.  FERNALD. 

In  reply  to  the  above  letter  Professor  Altum  wrote  as 
follows  :  — 

I  have  never  known  of  a  devastation  in  Germany  equal  in  severity 
and  extent  to  that  in  your  country.  So  far  as  I  know,  all  of  the 
devastations  of  dispar  in  this  region  have  occurred  on  limited 
areas,  and  have  always  quickly  disappeared. 


288  THE   GYPSY  MOTH. 

An  importation  of  predaceous  insects  to  oppose  this  destructive 
dispar,  e.  g.,  Calosoma  sycoplianta,  etc.,  cannot  possibly  be  of 
any  industrial  importance.  These  work  in  no  noteworthy  degree 
even  in  our  far  smaller  dispar  calamities.  There  are  small  para- 
sitic insects,  especially  the  species  of  Microgaster,  and  even  mi- 
crobes (bacteria) ,  which  are  valuable.  But  these  can  only  be 
collected  and  sent  away  when  they  appear  in  multitudes,  and  I  do 
not  know  at  present  of  a  single  case  in  which  there  is  such  an 
appearance. 

I  can  only  recommend  a  single  successful  artificial  remedy, 
namely,  painting  or  moistening  the  egg-clusters  with  liquid  fat 
(oil,  petroleum,  train  oil)  or  with  thin  liquid  wagon  grease,  raupen- 
leim,  etc.  With  brushes  having  long  handles,  and  also  by  the  use 
of  ladders,  most  of  the  egg-clusters  can  be  reached.  As  a  rule, 
these  egg-clusters  stand  out  visibly  from  the  darker  green  bark  of 
the  trunks  and  branches,  the  under  side  of  which  may  be  cleaned 
with  a  brush  attached  to  a  pole.  This  work  can  be  done  from 
September  to  April,  and  has  always  been  a  complete  success  here  ; 
but  with  such  an  enormous  and  extensive  development  as  dispar 
presents  with  you,  the  successful  execution  of  the  above  method 
of  destruction  does  not  seem  possible  ;  moreover,  no  other  artificial 
method  is  of  value.  You  will,  therefore,  for  the  present,  make 
use  of  this  method  where  the  insect  appears  in  small  numbers,  or 
as  single  individuals  beyond  the  area  being  destroyed,  and  also 
where  the  first  colonies  or  gathering  points  appear,  that  is  to  say, 
where  a  great  development  of  the  insect  is  feared.  Here  the  in- 
sects are  in  such  numbers  that  it  is  possible  to  destroy  them,  and 
are,  for  the  most  part,  to  be  found  on  the  lower  portion  of  the 
trunks  of  the  trees,  where  they  can  be  easily  reached  by  the  hand 
or  with  short-handled  brushes.  These  later  central  points  of  the 
invasion  usually  have  a  small  area  and  definite  borders,  and  such 
a  method  of  destruction  must  be  adopted  and  carried  on  with  all 
possible  energy,  for  the  protection  of  the  surrounding  territory. 
It  is  needless  to  say  that  the  caterpillars,  pupae  and  female  moths 
should  be  destroyed. 

THE  EGGS. 

The  eggs  (Plate  I,  Figs.  9  and  10)  are  nearly  globular, 
slightly  flattened  on  the  lower  side,  and  generally  flattened 
or  depressed  on  the  upper  side.  They  are  about  one-twen- 
tieth of  an  inch  (1.5  mm.)  in  lateral  diameter,  and  of  a  dark 
salmon  color  when  first  laid ;  but  when  fertile  they  change 
to  a  darker  color,  owing  to  the  development  of  the  embryo, 
which  is  quite  fully  formed  in  about  three  weeks.  The  egg 


PLATE  41 


Mass  of  pupa-cases  and  egg-clusters  under  a  fence  rail. 


THE  EGGS.  289 

appears  to  be  smooth,  when  examined  with  a  lens,  but  if  the 
shell  be  very  carefully  removed  and  examined  under  a  half- 
inch  objective,  or  a  higher  power,  it  exhibits  somewhat 
irregular  hexagonal  marks  over  the  entire  surface,  except  at 
the  centre  of  the  depression  above,  which  is  occupied  by  the 
micropyle  with  its  surrounding  rosette.  This  consists  of 
three  rows  of  somewhat  pear-shaped  cells,  each  row  over- 
lapping a  part  of  the  next  outside  of  it  (Plate  58,  Figs. 
11  and  12).  The  most  successful  method  found  for  ren- 
dering the  micropyle  and  surface  markings  visible  was  to 
remove  the  contents  of  the  egg  'and  mount  the  shell  dry. 
When  mounted  in  Canada  balsam,  glycerine  or  glycerine 
jelly,  all  the  markings  were  obliterated.  It  was  impossible 
to  obtain  any  better,  or  even  as  good,  results  by  first  stain- 
ing the  shells  in  hsematoxylin,  eosin,  aniline  red,  aniline 
blue,  picro-carmine  or  methyl  green.  This  last  stain,  how- 
ever, gave  better  results  than  any  of  the  others. 

The  eggs  are  laid  in  the  summer,  soon  after  the  emergence 
of  the  moths,  in  oval  or  rounded  clusters  (Plate  I,  Fig.  8), 
usually  containing  from  four  hundred  to  five  hundred  eggs, 
but  clusters  have  been  found  which  contained  one  thousand 
eggs.  These  egg-clusters  vary  in  size  from  one-half  an  inch 
to  one  and  one-half  inches  in  length,  and  from  one-third  of 
an  inch  to  one  inch  in  width.  The  average  dimensions  of 
fifteen  clusters  were  found  to  be  21^  mm.  long,  11|  mm. 
wide  and  5|  mm.  deep.  The  female  covers  the  eggs,  as 
she  deposits  them,  with  the  yellowish  hairs  from  the  under 
side  and  end  of  the  abdomen,  which  cause  the  cluster  to  re- 
semble a  small  piece  of  sponge  in  general  appearance  (Plate 
I,  Fig.  8).  In  time,  however,  they  fade,  and  more  nearly 
resemble  the  eggs  of  the  white  marked  tussock  moth  (Plate 
39,  Fig.  15).  The  female  deposits  her  eggs  in  every  con- 
ceivable place,  as  on  the  branches  and  trunks  of  trees  (Plate 
55),  often  below  the  surface  of  the  ground  when  this  has 
shrunken  away  from  the  tree ;  in  cavities  in  trees  or  other 
concealed  places  ;  under  bark  which  has  separated  from  dead 
branches ;  under  bands  of  tarred  paper  or  cards  tacked  upon 
the  trees ;  in  stone  walls ;  under  stones  and  in  cavities  in  the 
ground ;  in  old  tin  cans,  on  dead  leaves  or  other  rubbish 
near  the  infested  trees;  under  fence  rails  (Plate  41)  or  the 


290  THE  GYPSY  MOTH. 

loose  boards  or  timbers  of  barns  or  out-buildings  ;  in  birds' 
nests,  and  many  other  places,  occasionally  on  leaves  on  the 
tree  and  sometimes  on  the  fruit ;  but  undoubtedly  the  trunks 
and  branches  of  the  trees  (Plate  42)  are  the  most  natural 
places.  As  a  rule,  the  eggs  on  the  limbs  are  laid  on  the 
under  side,  although  in  a  few  instances  they  have  been  found 
on  the  upper  side,  but  more  or  less  concealed.  In  one  case 
an  egg-cluster  was  found  on  a  piece  of  old  rope  hanging  from 
a  tree,  and  another  on  a  thermometer  hanging  against  the 
outside  of  a  chimney.  It  is  not  an  uncommon  thing  to  find 
them  in  tent  caterpillars'  nests,  and  one  was  found  deposited 
on  a  spider's  web  on  a  fence. 

The  typical  form  of  an  egg-cluster  is  elongated  and  slightly 
narrowed  at  the  end  last  laid.  This  form  is  subject  to  all 
imaginable  variations,  according  to  the  conditions  under 
which  the  mass  of  eggs  is  laid.  In  one  instance,  six  appar- 
ently complete  egg-clusters  were  observed  that  had  been  laid 
nearly  on  top  of  each  other ;  and  in  another,  a  female  that 
appeared  to  have  died  on  her  egg-cluster  was  nearly  half 
covered  with  eggs  deposited  by  a  second  moth  while  laying 
close  by.  Eggs  laid  by  unfertilized  females  are  usually 
poorly  covered  with  hair,  and  crippled  females,  as  well  as 
those  which  have  trouble  about  emerging,  often  leave  a  large 
part  of  the  hair  of  the  abdomen  in  the  pupal  case.  Eggs 
laid  by  such  females  are  usually  stuck  together  in  a  loose 
mass,  poorly  covered  and  easily  separated.  The  adhesive 
substance  by  which  the  eggs  are  attached  to  each  other  and 
to  the  surface  upon  which  they  are  deposited,  as  well  as  that 
which  causes  the  hairs  of  the  abdomen  to  adhere  to  them,  is 
insoluble  in  dilute  or  absolute  alcohol,  chloroform  or  spirits 
of  turpentine. 

SCATTERED  EGGS. 

In  nearly  every  case  where  a  fertilized  female  was  confined 
in  a  box,  she  was  found  to  scatter  eggs  while  laying.  The 
eggs  were  dropped  accidentally,  the  moth  being  unable  to 
attach  them  to  the  surface  on  which  she  rested.  Frequently 
a  considerable  number  were  dropped  before  she  succeeded  in 
attaching  a  single  egg ;  but  after  a  small  number  had  been 
securely  deposited,  fewer  eggs  were  scattered,  although  occa- 
sionally they  were  dropped  throughout  the  entire  process  of 


PLATE  42.     Mass  of  egg-clusters  on  the  trunk  of  a  large  elm. 


SCATTERED  EGGS.  291 

laying.  The  most  marked  cases  of  egg-scattering  were  those 
where  the  moth  did  not  first  form  a  hairy  area  on  which  to 
deposit  eggs.  Observations  made  on  the  egg-scattering  of 
fifteen  gypsy  moths,  ten  in  the  insectary  and  five  on  trunks 
of  trees  in  the  field,  showed  that  all  of  them  scattered  eggs, 
some  of  which  were  dropped  before  the  moth  mated  and 
others  afterwards.  The  number  of  eggs  scattered  by  these 
insects  ranged  from  one  to  thirty-four,  the  average  being 
nine  and  three-fourths.  Male  moths,  when  numerous,  in 
attempting  to  mate  with  females  while  they  are  laying,  often 
disturb  them  to  such  an  extent  as  to  cause  them  to  drop  or 
scatter  eggs.  Eggs  scattered  by  fertilized  females  have 
proved  to  be  fertile.  Observations  made  in  the  field  show 
that  many  eggs  are  scattered  by  the  moths  when  laying 
under  the  most  natural  conditions.  In  one  colony  in  Sau- 
gus,  in  1894,  the  greatest  number  of  egg-clusters  were  on 
the  rough  bark  of  pine  trees,  and  many  scattered  eggs  were 
found  at  the  base  of  these  trees  among  the  pine  needles. 
Nearly  all  of  these  eggs  were  naked,  and  in  many  cases  they 
were  loose,  though  some  were  attached  to  pine  needles  or  to 
fragments  of  bark  at  the  base  of  the  trees.  Scattered  eggs 
were  also  found  in  crevices  of  the  rough  bark  below  the 
clusters.  Eighty-five  per  cent,  of  the  scattered  eggs  taken 
at  this  place  proved  to  be  fertile.  This  scattering  of  eggs 
doubtless  explains  why  caterpillars  occur  in  places  where 
the  eggs  on  the  trees  have  been  destroyed  the  previous 
winter,  and  indicates  the  value  of  burlapping  as  a  supple- 
ment to  the  work  of  egg  destruction. 

RESISTANCE  or  EGGS  OF  THE  GYPSY  MOTH  TO  THE  ACTION 

OF  THE  ELEMENTS. 

In  January,  1895,  a  number  of  egg-clusters  were  thor- 
oughly broken  up,  so  that  the  eggs  were  entirely  separated, 
and  as  much  of  the  hair  removed  as  possible.  The  eggs 
from  each  cluster  were  then  placed  in  a  small  paper  box 
which  was  covered  with  two  thicknesses  of  thin,  open  cheese- 
cloth. Six  of  the  clusters  were  placed  underneath  the  store- 
house, where  they  were  sheltered  from  storms,  but  otherwise 
wholly  exposed  to  all  climatic  changes ;  and,  to  determine 
the  effect  of  the  actual  out-door  exposure,  six  more  egg- 


292  THE   GYPSY  MOTH. 

clusters  were  taken  from  trees,  and,  after  being  prepared  in 
the  same  manner,  were  placed  in  exposed  positions  on  the 
ground,  in  the  centre  of  a  colony.  The  tops  of  the  boxes 
were  placed  uppermost,  so  as  to  give  free  access  to  rains, 
and  the  localities  marked,  so  that  they  might  be  readily  found. 
The  boxes  were  allowed  to  remain  here  through  all  the  cold 
weather  and  storms  of  the  season,  sometimes  being  bare,  and 
sometimes  covered  by  the  ice  formed  from  the  melting  snow. 

On  the  4th  of  April,  all  of  these  egg-clusters,  as  well  as 
those  from  underneath  the  storehouse,  were  collected  and 
placed  in  the  hatching-boxes.  Those  from  the  colony  were 
more  or  less  covered  with  d&bris  which  had  been  carried  into 
the  box  by  the  action  of  rain  or  of  thawing  ice.  All  of  the 
egg-clusters  hatched  from  April  16  to  April  20,  and,  judging 
from  the  small  number  of  eggs  remaining  unhatched,  pro- 
duced as  many  caterpillars  as  similar  clusters  which  had  been 
kept  intact,  either  in  cold  storage  or  out  of  doors,  during 
the  winter. 

From  this  it  is  evident  that,  although  the  hairy  covering 
of  the  egg-cluster  may  serve  in  a  measure  as  a  protection  to 
the  eggs,  yet  it  is  not  essential  to  their  successful  hiber- 
nation. Certain  European  writers  recommend  scraping  the 
eggs  from  the  trees,  and  state  that  when  this  is  done  their 
vitality  is  destroyed  by  the  severity  of  winter.  This  cer- 
tainly is  not  true  in  Massachusetts,  even  if  it  be  so  in 
Europe. 

EFFECT  OF  EXTEEMES  OF  TEMPERATURE  ON  THE  EGGS  OF 
THE  GYPSY  MOTH. 

During  the  spring  of  1895,  considerable  time  was  devoted 
to  studying  the  effect  of  heat  and  cold,  in  extreme  degrees, 
upon  the  eggs  of  the  gypsy  moth,  with  a  view  of  obtaining 
a  better  knowledge  of  the  capabilities  of  this  insect  to  resist 
such  extremes,  which  fact  has  a  bearing  in  showing  whether 
sudden  climatic  changes  would  aid  in  holding  the  insect  in 
check. 

The  experiments  with  extremes  of  heat  were  conducted  by 
use  of  a  hot- water  oven,  the  necessary  degree  of  heat  being 
obtained  by  means  of  a  small  oil  stove,  and  the  temperature 
of  the  interior  being  indicated  by  a  small  thermometer. 


EXPERIMENTS  ON  EGGS.  293 

To  obtain  extremes  of  cold,  the  eggs  were  placed  in  vials 
and  enclosed  in  a  small  can,  which  was  then  placed  in  an- 
other can  containing  a  freezing  mixture  (composed  of  equal 
parts  of  coarse  granulated  snow  and  salt,  and  in  some  cases 
one  which  was  composed  of  four  parts  of  snow  and  five  parts 
of  calcium  chloride).  The  degree  of  cold  was  indicated  by 
a  thermometer  placed  in  the  freezing  mixture,  and  so  ar- 
ranged as  to  be  easily  read  through  a  glass  window  in  the 
side  of  the  can. 

Effect  of  Heat  on  Eggs. 

On  April  3,  ten  egg-clusters  of  the  gypsy  moth  were  ex- 
posed for  thirty  minutes  to  a  temperature  of  80°  F.  They 
were  then  placed  in  the  hatching-boxes,  where  the  temper- 
ature was  normal,  and  daily  observations  made  until  April 
16,  when  all  the  egg-clusters  were  found  to  have  hatched. 
April  3,  ten  egg-clusters  were  exposed  for  thirty  minutes 
to  a  temperature  of  90°,  and  were  then  placed  in  hatching- 
boxes ;  all  of  the  clusters  had  hatched  April  16.  April 
3,  ten  egg-clusters  were  exposed  for  thirty  minutes  to  a 
temperature  of  100°,  and  then  placed  in  hatching-boxes ;  by 
April  17,  all  had  hatched.  April  3,  ten  egg-clusters  were 
exposed  for  thirty  minutes  to  a  temperature  of  110°,  and 
then  placed  in  hatching-boxes ;  on  the  17th  of  April  all  of 
these  egg-clusters  had  hatched.  March  26,  three  egg-clusters 
were  exposed  for  thirty  minutes  to  a  temperature  of  120°, 
and  then  placed  in  hatching-boxes ;  one  of  these  hatched 
April  7  and  the  other  two  on  April  9.  On  April  3,  ten  egg- 
clusters  were  exposed  for  thirty  minutes  to  a  temperature  of 
130°,  and  then  placed  in  hatching-boxes;  on  April  12,  all 
of  these  egg-clusters  commenced  hatching.  Having  obtained 
this  result,  they  were  further  experimented  with  by  being 
placed  in  a  cold  box  surrounded  by  ice  and  salt,  and  ex- 
posed for  thirty  minutes  to  a  temperature  ranging  from  zero 
to  8°  below;  none  of  the  egg-clusters  hatched  after  this 
treatment.  April  15,  ten  egg-clusters  were  exposed  for  a 
period  of  fifteen  minutes  to  a  temperature  of  140°;  none 
hatched.  April  16,  six  egg-clusters  were  exposed  to  a  tem- 
perature of  150°  for  a  period  of  fifteen  minutes,  and  then 
placed  in  the  hatching-boxes  ;  none  hatched. 


294  THE  GYPSY  MOTH. 

From  the  above  experiments  we  conclude  that  a  temper- 
ature of  at  least  140°  is  necessary  to  destroy  the  vitality  of 
the  developed  embryo  in  the  egg.  In  March,  1895,  the 
effect  of  the  naphtha  torch  flame  was  tried  upon  egg-clus- 
ters, exposing  them  to  the  action,  of  the  flame  for  various 
short  periods  of  time.  This  apparatus  is  sometimes  used  for 
destroying  eggs  laid  in  cavities  in  trees.  Of  thirty-one  egg- 
clusters  treated  in  this  manner  none  hatched. 

Effect  of  Cold  on  Eggs. 

Experiments  in  rapidly  changing  egg-clusters  from  a  high 
to  a  low  temperature  were  conducted  with  the  following  re- 
sults :  March  22,  1895,  four  egg-clusters  were  changed  in 
twenty  minutes  from  a  temperature  of  80°  above  zero  to  5° 
above,  and  left  over  night  in  a  freezing  mixture'  of  calcium 
chloride  and  snow.  Two  of  the  egg-clusters  hatched  April  9 
and  two  April  11.  Apparently  these  egg-clusters  hatched 
as  well  as  the  average  ones  in  the  field,  and  the  caterpillars 
from  them  fed  and  grew  in  as  satisfactory  a  manner  as 
normal  caterpillars.  March  26,  two  egg-clusters  were  ex- 
posed for  some  time  to  a  temperature  of  80°  F.  They  were 
then  packed  in  a  mixture  of  calcium  chloride  and  snow,  and 
in  fifteen  minutes  reduced  to  a  temperature  of  20°  below 
zero,  a  fall  of  100°.  They  were  kept  at  this  temperature  for 
thirty  minutes,  and  then  taken  out  and  placed  in  the  hatch- 
ing-box. By  the  16th  of  April  all  had  hatched. 

DATE  OF  HATCHING. 

The  eggs  of  the  gypsy  moth  hatch  in  the  spring,  from  the 
last  of  April  to  the  middle  of  June,  depending  on  the  weather 
and  the  places  in  which  they  are  deposited,  those  eggs  which 
are  laid  in  warm,  sunny  places  hatching  the  earliest,  while 
those  that  are  laid  in  cold  places,  being  protected  from  the 
heat  of  the  sun,  hatch  much  later.  The  earliest  recorded 
date  of  hatching  in  the  field  was  April  1,  1892,  in  Medford, 
and  on  May  14  of  the  same  year  a  large  part  of  the  eggs  in 
warm,  sunny  places  had  hatched.  The  latest  date  noted  was 
June  17. 

The  embryo  develops  very  rapidly,  especially  in  a  warm 
temperature.  Eggs  laid  Aug.  10,  1894,  showed  well-de- 


SECOND  BROOD.  295 

veloped  embryos  August  26,  and  eggs  were  found  in  the 
field,  Aug.  18,  1894,  that  contained  mature  embryos  1.4  mm. 
long.  Notwithstanding  this  early  development  of  the  em- 
bryo, up  to  this  year  no  eggs  were  found  to  have  hatched 
in  the  fall,  though  a  careful  watch  was  kept  for  them.  In 
Europe  fall  hatching  is  reported  in  at  least  one  instance. 
Ratzeburg,  in  "  Die  Forst-Insecten,"  Vol.  II,  page  112,  says  : 
"  Here  they  remain  [on  the  branches]  much  like  a  long  mass 
of  fungus  until  the  next  April  or  May,  or  by  exception  they 
hatch  in  the  autumn,  as  I  have  seen  them  myself  on  the 
5th  of  September,  1836." 

A  SECOND  BROOD. 

In  the  early  part  of  September,  1895,  many  of  the  gypsy 
moth  egg-clusters  were  found  to  be  hatching  at  the  ' '  Win- 
ning "  colony,  in  Woburn,  where  the  caterpillars  had  com- 
mitted serious  depredations  during  the  summer  months. 
The  second  brood,  which  appeared  only  in  this  particular 
colony,  seemed  to  have  hatched  because  of  peculiar  condi- 
tions of  location  and  temperature.  The  colony  is  situated 
on  the  side  of  a  hill,  sloping  towards  the  south,  which  is 
covered  with  a  dense  growth  of  medium-sized  oak  trees. 
When  this  colony  was,  discovered,  in  the  early  part  of  the 
summer,  the  caterpillars  were  much  larger  and  more  nearly 
ready  to  pupate  than  in  any  other  colony,  and  this  led  to  the 
opinion  that  the  eggs  must  have  hatched  much  earlier  than 
in  other  localities.  Many  of  the  moths  emerged  and  laid 
their  eggs  at  this  place  before  the  caterpillars  in  other  colo- 
nies, where  the  conditions  for  rapid  development  were  not 
as  favorable,  had  commenced  to  pupate. 

While  embryonic  development  in  this  insect  appears  to  be 
more  rapid  in  warm  weather,  a  limited  number  of  experi- 
ments performed  in  1893  and  1894,  seem  to  indicate  that  a 
certain  degree  of  cold  is  probably  necessary  to  mature  the 
embryo.  In  the  latter  part  of  August  on  several  nights  the 
temperature  fell  quite  low  in  the  eastern  part  of  the  State, 
and  on  one  night  a  frost  occurred  in  some  places.  At  this 
time  a  part  of  the  eggs  in  the  ' '  Winning  "'  colony  had  been 
deposited  from  four  to  six  weeks,  which  was  sufficient  time 
for  the  development  of  the  embryo.  This  cool  weather  was 


296  THE   GYPSY  MOTH. 

followed  by  a  hot  wave,  during  which  a  thermometer,  ex- 
posed to  the  direct  rays  of  the  sun  at  Maiden,  reached  a 
temperature  of  112°  F.  This  extremely  hot  weather  caused 
a  part  of  the  eggs  in  this  colony  to  hatch,  thus  giving  rise  to 
a  second  brood,  although  in  no  case  was  the  hatching  com- 
plete, as  only  a  few  eggs  (one  to  twenty-five)  hatched  from 
a  cluster.  Eggs  brought  to  the  insectary,  and  kept  at  an 
average  temperature  of  70°,  gave  rise  to  a  few  caterpillars, 
from  time  to  time,  for  more  than  a  month. 

A  number  of  the  caterpillars  from  this  second  brood  were 
collected  and  sacked  in  on  a  small  red  oak  tree,  and  others 
were  taken  to  the  insectary  and  fed  daily.  At  the  time  of 
this  writing  (Dec.  5,  1895)  a  part  of  the  latter  have  pupated. 
Careful  observations  were  made  upon  the  caterpillars  sacked 
in  on  the  tree,  and  also  upon  those  which  were  feeding  under 
natural  conditions  in  the  colony.  In  neither  case  were  they 
found  to  thrive  in  a  normal  manner,  and  with  cooler  weather 
and  frosty  nights  they  gradually  died,  until  none  were  left. 
Those  which  survived  longest  had  nearly  all  entered  the 
second  molt.  The  caterpillars  reared  at  the  insectary  did 
not  show  as  much  strength  and  vigor  as  those  which  hatched 
normally  in  the  spring,  and  over  seventy-five  per  cent,  of 
them  died  before  reaching  the  fifth  molt. 

While  this  is  the  only  positive  record  of  a  second  brood 
of  the  gypsy  moth  in  this  country,  it  is  presumably  true  that 
in  some  cases  egg-clusters  may  have  partly  hatched  in  the 
fall  of  previous  years.  Any  egg-cluster  taken  in  the  field, 
which  possesses  marked  peculiarities,  is  usually  sent  to  the 
insectary  for  examination,  and  many  of  the  clusters  thus  sent 
in  during  the  winter  and  spring  ot  1894-95,  were  found  to 
contain  empty  egg-shells.  The  size  and  appearance  of  the 
holes  in  the  shells  indicated  that  it  was  not  the  work  of  mites, 
since  they  eat  out  a  ragged,  irregular  opening,  while  the  hole 
left  by  the  exit  of  the  young  caterpillar  has  a  more  regular 
outline,  and  varies  from  a  small  circular  aperture  to  a  nar- 
row band  eaten  around  the  entire  periphery  of  the  shell. 
After  studying  a  number  of  these  egg-clusters  during  the 
spring  of  the  present  year,  Mr.  Kirkland  suggested  that 
fall  hatching  would  best  explain  the  occurrence  of  the  empty 
egg-shells ;  but  at  that  time  there  was  no  positive  evidence 


HATCHING  OF  THE   EGGS.  297 

that  such  hatching  had  actually  taken  place  in  the  infested 
district.  In  the  light  of  our  present  knowledge,  however, 
it  seems  probable  that  fall  hatching  may  have  occurred  occa- 
sionally during  previous  years,  and  also  that,  under  the  most 
favorable  conditions,  this  insect  shows  a  tendency  to  be- 
come double-brooded,  like  the  related  species  of  the  genus 
Orgyia, 

The  death  of  the  caterpillars  of  the  second  brood,  feeding 
in  the  field,  was  to  be  expected,  since  the  season  was  not  long 
enough  to  permit  them  to  reach  maturity.  Even  if  they  had 
matured  it  is  doubtful  if  the  caterpillars  would  have  seriously 
injured  trees  which  had  retained  their  foliage  throughout  the 
summer. 

On  the  softer  and  more  delicate  foliage  of  those  trees 
which  had  leaved  out  a  second  time,  after  being  stripped 
early  in  the  season,  the  caterpillars  fed  with  great  avidity, 
and,  had  the  length  of  the  season  permitted,  such  trees  might 
have  been  injured  to  a  considerable  degree. 

HATCHING  OF  THE  EGGS. 

The  majority  of  the  eggs  hatch  during  the  warm  part  of 
the  day,  from  10  A.M.  to  2  P.M.,  and  continue  hatching  for 
several  days.  It  is  apparent  that,  when  hatching,  the  cater- 
pillar first  eats  a  hole  through  the  side  of  the  egg-shell,  the 
flattened  surfaces  representing  the  top  and  bottom  of  the 
egg,  and  then  eats  more  or  less  of  a  band  around  the  shell 
on  the  side,  often  leaving  only  the  upper  and  lower  surfaces 
of  the  egg.  Sometimes  the  caterpillar  emerges  from  the 
egg  by  a  single  hole  in  the  side,  but  usually  it  eats  a  band 
around  the  side  of  the  egg,  leaving  only  the  upper  and  lower 
disks  remaining. 

NUMBER   OF   CATERPILLARS   FROM  SINGLE   EGG-CLUSTERS, 
AND  TlME  REQUIRED  FOR  HATCHING. 

From  one  egg-cluster  that  had  been  kept  in  a  warm  room  at 
the  insectary  during  the  winter  of  1893-94,  1  egg  had  hatched 
Feb.  23,  1894,  at  9  A.M.  ;  at  10  A.M.,  49  more;  at  11  A.M., 
13  more  ;  and  at  5  P.M.,  50  more,  making  113  which  hatched 
the  first  day. 


298  THE   GYPSY  MOTH. 

February  24,  at  noon,  80  more  eggs  had  hatched ;  at  5 
P.M.,  43  more  from  the  same  cluster,  or  123  on  the  second 
day. 

February  25,  at  10  A.M.,  20  more  eggs  had  hatched;  at 
1.15  P.M.,  47  more;  and  at  6.15  P.M.,  6  more,  making  73 
eggs  which  hatched  on  the  third  day. 

February  26,  at  7.30  A.M.,  87  more  had  hatched ;  at  1.30 
P.M.,  172,  and  at  5  P.M.,  16  more,  or  275  on  the  fourth  day. 

February  27,  at  7  A.M.,  39  more  had  hatched ;  and  at  5.40 
P.M.,  43  more,  making  82  for  the  fifth  day. 

February  28,  at  7  A.M.,  2;  at  noon,  26 ;  at  5  P.M.,  no 
more  had  hatched,  making  28  eggs  which  hatched  on  the 
sixth  day. 

March  1,  at  7  A.M.,  2  more  eggs  had  hatched;  at  noon,  5  ; 
and  at  5  P.M.,  2  more,  making  9  for  the  seventh  day. 

March  2,  at  7.20  A.M.,  1  more  egg  had  hatched;  and  at 
5  P.M.,  1  more,  making  2  that  hatched  on  the  eighth  day. 

March  3,  at  7.45  A.M.,  1  more  egg  had  hatched.  No  other 
eggs  hatched  from  this  cluster.  The  total  number  of  eggs 
hatched  from  the  cluster,  in  nine  days,  was  706.  From 
another  egg-cluster,  kept  under  similar  conditions,  997 
hatched  in  eleven  days. 

To  gain  further  information  concerning  the  actual  number 
of  caterpillars  which  may  hatch  from  one  egg-cluster,  and  the 
time  required  for  hatching,  a  number  of  egg-masses  which 
had  been  taken  from  the  field  were  brought  into  a  warm 
room  and  placed  in  boxes,  April  25,  1895.  The  caterpillars 
were  counted  and  then  removed  as  soon  as  hatched.  From 
egg-cluster  No.  1,  250  caterpillars  were  hatched  in  2  days  and 
22  hours.  From  egg-cluster  No.  2,  408  caterpillars  were 
hatched  in  3  days,  17  hours  and  10  minutes.  From  egg- 
cluster  No.  3,  708  caterpillars  were  hatched  in  3  days,  17 
hours  and  15  minutes.  From  egg-cluster  No.  4,  679  cater- 
pillars were  hatched  in  3  days  and  1  hour.  From  egg- 
cluster  No.  5,  393  caterpillars  were  hatched  in  3  days,  22 
hours  and  30  minutes.  From  egg-cluster  No.  6,  438  cater- 
pillars were  hatched  in  4  days,  16  hours  and  45  minutes. 
The  whole  number  of  caterpillars  from  the  six  egg-clusters 
was  2,876,  an  average  of  479  to  each  cluster.  The  average 
time  in  hatching  was  3  days,  20  hours  and  6|  minutes. 


THE   CATERPILLAR.  299 

From  studies  made  on  a  large  number  of  egg-clusters  in 
the  insectary,  supplemented  by  observations  in  the  field,  it 
was  discovered  that  in  many  cases  some  part  of  the  eggs 
composing  an  egg-cluster  did  not  hatch.  Seven  large  egg- 
clusters  which  had  hatched  were  found  to  contain  on  an 
average  124  unhatched  eggs,  the  smallest  number  being  43, 
the  largest  224.  A  small  number  of  unhatched  eggs  is  found 
in  nearly  all  the  old  nests  taken  in  the  field. 

THE  LARVA  OK  CATERPILLAR. 

Relative  Vitality  of  Caterpillars  hatching  at  Different  Times 
from  the  Same  ^Egg-cluster. 

The  following  observations  were  made  under  my  directions 
by  Messrs.  Minott  and  Mosher,  both  careful  and  reliable 
observers  :  — 

From  a  large  cluster  of  eggs,  laid  by  a  single  female 
gypsy  moth,  and  kept  in  a  warm  room,  4  hatched  late  in  the 
afternoon  of  March  11,  1894;  at  10  A.M.,  March  13,  333 
more  eggs  had  hatched ;  at  5.20  P.M.,  194  more  had  hatched ; 
March  14,  233  had  hatched;  March  15,  at  4.35  P.M.,  48 
more  eggs  had  hatched ;  March  19,  10  more  hatched  ;  March 
20,  3 ;  and  on  the  21st,  6  more  eggs  hatched,  making  831 
eggs  hatched  from  this  cluster.  The  caterpillars  were  re- 
moved as  soon  as  hatched. 

Fifty  caterpillars  were  selected,  as  follows:  10  of  those 
hatched  on  the  second  day,  10  of  those  hatched  on  the  third 
day,  10  of  those  hatched  on  the  fourth,  10  of  those  hatched 
on  the  eighth  and  5  of  those  hatched  on  the  ninth  and  tenth 
days,  making  6  sets  of  caterpillars  taken  from  those  which 
hatched  at  different  times.  Each  caterpillar  was  fed  on  let- 
tuce, in  a  box  by  itself,  and  under  as  nearly  similar  con- 
ditions as  possible,  careful  records  being  made,  for  the  pur- 
pose of  learning  whether  there  was  any  difference  in  the 
vitality  of  caterpillars  hatched  at  different  times,  from  the 
same  egg-cluster ;  the  period  of  rest  before  and  after  each 
molt,  and  the  time  between  each  molt.  No  perceptible  dif- 
ference was  noticed  in  the  vitality  of  those  hatched  at  differ- 
ent times.  It  was  observed  that  they  all  ate  equally  well 
and  appeared  equally  healthy,  and  that  all  their  transforina- 


300  THE  GYPSY  MOTH. 

tions  agreed  very  closely,  except  that  those  which  hatched 
latest  did  not  require  as  many  days  in  their  molts,  and  there- 
fore reached  the  adult  stage  as  soon  as  the  others,  although 
marked  variations  occurred  among  the  individuals  of  each 
hatch  (Plate  43).  Some  grew  faster  than  others,  while  some 
appeared  to  eat  about  the  same  amount  as  others  and  yet  did 
not  grow  as  rapidly. 

Description  of  the  Larva  or  Caterpillar. 

The  following  descriptions  were  prepared  from  the  study 
of  from  twenty-five  to  fifty  caterpillars  in  each  stage  :  — 

First  Larval  Stage.  —  The  larva,  when  first  hatched,  is 
3.6  mm.  (about  fourteen  hundredths  of  an  inch)  in  length,  and 
the  head  is  .6  mm.  (about  twenty-three  thousandths  of  an  inch) 
in  width  and  somewhat  thicker  than  the  body,  shining  black, 
with  a  few  (about  forty )  pale-yellow  hairs  scattered  over  the 
surface,  the  longest  of  which  are  not  quite  equal  to  the  width 
of  the  head.  There  are  a  few  additional  hairs  on  the  mouth 
parts.  The  body  is  more  or  less  cylindrical,  slightly  taper- 
ing toward  the  posterior  part  which  is  blunt  and  rounded. 
When  first  hatched  they  are  a  pale  brownish-yellow,  with  a 
brown  spot  on  the  forward  side  of  segments  four  to  twelve 
inclusive,  on  the  subdorsal  line  of  each  side,  but  the  ground 
color  grows  darker  within  a  few  hours.  The  subdorsal  tuber- 
cles of  the  second  segment  (first  after  the  head)  are  elon- 
gated laterally  and  joined  at  the  dorsal  line.  These  are  of 
a  dark-brown  color.  The  lateral  tubercles  of  this  segment 
are  fused,  forming  one  very  large  lateral  tubercle  on  each 
side,  which  extends  obliquely  out  and  forward.  The  third 
and  fourth  segments  have  three  tubercles  on  each  side,  one 
subdorsal,  one  lateral  and  one  stigmatal.  The  remaining 
segments,  except  the  last,  have  large  subdorsal  and  lateral 
tubercles,  the  latter  being  so  large  as  to  fuse  more  or  less 
completely  with  those  above  them.  There  are  three  nearly 
equal-sized  tubercles  on  each  side  of  the  last  segment,  so 
arranged  as  to  form  an  arched  row  around  the  posterior  end 
of  the  animal. 

The  insect  at  this  stage  has  two  kinds  of  hairs  arising 
from  the  tubercles,  the  first  of  which  (Plate  48,  Fig.  8)  is 
about  as  long  as  the  thickness  of  the  body,  of  a  pale-brown 


I 


PLATE  43.  Variation  in  size  of  caterpillars  of  the  same  age- 
Fifty  caterpillars  hatched  from  the  same  egg-cluster 
were  reared  separately  on  lettuce  leaves,  all  receiving 
exactly  the  same  treatment.  When  the  caterpillars  -were 
five  weeks  old,  the  two  extremes  in  size,  together  with 
a  caterpillar  of  medium  size,  were  photographed.  The 
smallest  caterpillar  as  here  shown  has  not  molted.  The 
medium  caterpillar  has  molted  twice.  The  largest  has 
molted  four  times  and  is  approaching  the  fifth  molt. 


THE   CATERPILLAR.  301 

color,  smooth  throughout,  with  a  sharp  point  at  the  outer 
end ;  and  at  the  basal  third  they  have  an  inflated  globule, 
the  diameter  of  which  is  three  times  as  great  as  that  of  the 
hair.  The  walls  of  this  globule  are  delicate,  and  when  the 
insect  is  alive  they  are  fully  distended,  probably  with  air  or 
gas ;  but  when  dead  they  collapse  more  or  less  completely, 
often  causing  the  hair  to  be  bent  at  this  place.  The  first 
and  second  rows  of  tubercles  on  each  side  have  only  hairs 
of  this  kind  on  them.  Similar  hairs  occur  on  the  larva  of 
the  nun  moth  (Lymantria  monacha)  before  the  first  molt, 
and  have  been  called  serostatic  hairs  by  Wachtl  and  Kor- 
nauth,  and  the  globules  serophores.  These  authors  believe 
that  these  inflated  globules  have  the  effect  of  small  balloons, 
and  aid  in  transporting  the  young  caterpillars  to  a  consid- 
erable distance  when  the  wind  blows.  The  other  kind  of 
hairs  (filiform  hairs)  (Plate  48,  Fig.  9)  arise  from  the  two 
lateral  rows  of  protuberances,  and  are  unusually  long,  some 
of  them  being  longer  than  the  body  of  the  caterpillar ;  and 
they  have  several  longitudinal  rows  of  minute  barbs  extend- 
ing the  entire  length. 

Later  the  caterpillar  changes  color,  the  tubercles  becoming 
black,  the  body  reddish-brown  with  a  row  of  dull  reddish 
spots  along  the  middle  of  the  back,  one  each  on  the  fifth 
to  the  eleventh  segments  inclusive.  There  are  no  retractile 
tubercles  in  this  stage. 

The  time  between  hatching  and  the  first  molt,  of  twelve 
caterpillars  bred  in  confinement,  in  an  unheated  room,  was 
from  eight  to  twelve  days,  the  average  being  nine  and  one- 
fourth  days.  The  temperature  very  materially  affects  the 
time  before  molting,  for,  when  caterpillars  were  kept  in 
breeding  cages  near  warm  steam  pipes,  they  molted  in  five 
days;  while  others,  from  the  same  egg-cluster,  kept  in  a 
cool  part  of  the  room,  molted  in  seven  days. 

/Second  Larval  /Stage.  —  Length,  7  mm.  (about  twenty- 
seven  hundredths  of  an  inch),  and  the  head  is  1  mm.  (about 
thirty-nine  thousandths  of  an  inch)  in  width,  shining  black, 
with  numerous  fine,  pale-yellow  hairs  scattered  over  the  sur- 
face. Body,  dark  brown,  with  the  tubercles  black,  and  a 
somewhat  triangular  yellowish  spot  on  the  top  of  segments 
nine,  ten  and  eleven,  in  the  middle  of  which,  on  segments  ten 


302  THE   GYPSY  MOTH. 

and  eleven,  there  is  an  orange-colored  retractile  tubercle,  and 
also  one  on  each  side  of  the  dorsal  line,  near  the  front  edge 
of  segments  five,  six,  seven  and  eight,  of  the  same  color,  but 
much  smaller.  There  are  four  rows  of  tubercles  on  each  side, 
which,  named  from  above,  may  be  called  the  subdorsal,  the 
lateral,  the  stigmatal  and  the  substigmatal  row,  each  with  one 
tubercle  on  each  segment  after  the  head.  The  tubercles  of 
the  subdorsal  rows  on  the  second  segment  (first  after  the 
head),  on  the  front  half  of  the  segment,  are  subquadrate  in 
form,  and  but  slightly  separated  from  each  other  by  the  dorsal 
line.  The  subdorsal  tubercles  of  the  third  and  fourth  seg- 
ments are  smaller,  and  nearly  elliptical  in  outline,  while 
those  on  the  remaining  segments  are  larger  and  more  nearly 
circular.  The  tubercles  of  the  lateral  row  are  smaller  than 
those  above,  and  on  segments  five  to  thirteen  inclusive  they 
are  partially  fused  with  those  of  the  stigmatal  row ;  but  as 
they  are  a  little  further  forward  than  those  below,  the  fusion 
gives  an  obliquely  elongated  tubercle.  To  effect  this  fusion 
the  tubercles  of  these  two  rows  are  brought  towards  each 
other.  The  tubercle  of  the  stigmatal  row,  on  the  second  seg- 
ment, is  large,  somewhat  produced,  and  directed  obliquely 
forward.  The  substigmatal  row  consists  of  medium-sized 
tubercles,  lying  directly  above  the  legs  and  prolegs,  and 
about  half-way  between  them  and  the  stigmatal  row.  A  little 
below,  and  behind  these  tubercles,  on  segments  seven  to 
eleven  inclusive,  is  a  very  small  tubercle,  and  on  segments 
five,  six,  eleven  and  twelve  there  are  two  small  tubercles  on 
each  side  beneath,  the  inner  ones  being  much  the  smaller. 
The  tubercles  of  the  subdorsal  and  lateral  rows  are  armed 
with  black,  pointed  spines  and  a  few  pale-yellow  hairs,  while 
the  remaining  tubercles  are  armed  with  longer  pale-yellow 
hairs.  On  each  side  of  the  dorsal  line,  near  the  subdorsal 
tubercles,  on  segments  three  to  twelve  inclusive,  is  a  very 
small  tubercle,  with  one  black  spine  and  occasionally  a  few 
pale-yellow  hairs. 

Third  Larval  Stage. — Length,  10  mm.  (a  little  less  than 
one-half  of  an  inch),  immediately  after  molting,  and  the 
head  is  1.8  mm.  (about  seven  hundredths  of  an  inch)  in 
width,  shining  black,  with  numerous  pale-yellow  hairs  scat- 
tered over  the  surface.  The  general  color  of  the  body  is 


THE  CATERPILLAR.  303 

dark  brown  and  very  much  broken,  giving  the  appearance 
of  a  large  spot  on  each  segment.  The  lateral  lines  are  dull 
yellowish-white.  Arrangement  of  tubercles,  bristles  and 
hairs  as  in  the  last  stage. 

Fourth  Larval  Stage.  —  Length,  13  mm.  (about  half  an 
inch),  immediately  after  molting,  and  the  head  is  2.8  mm. 
(about  eleven  hundredths  of  an  inch)  in  width,  pale  brown- 
ish-white, mottled  on  the  sides  and  above  with  dark  brown, 
and  there  is  a  dark-brown  vertical  stripe  on  each  side  of  the 
clypeus  and  numerous  pale-yellow  hairs  scattered  over  the 
surface.  The  body  is  dark  brown,  finely  mottled  with  yel- 
low;  while  the  dorsal  line  is  pale  ochre-reddish,  enlarged 
into  small  grayish  spots  on  the  middle  of  the  sixth,  seventh 
and  eighth  segments,  and  on  the  ninth,  tenth  and  eleventh 
segments  there  are  larger  orange-colored  spots.  The  lat- 
eral line  is  pale  yellow,  and  below  this  the  surface  is  ashy, 
mottled  with  dark  brown.  The  tubercles,  spines  and  hairs 
are  as  in  the  preceding  stage. 

Fifth  Larval  Stage.  —  Length,  23  mm.  (about  nine-tenths 
of  an  inch),  immediately  after  molting.  The  head  is  3.6  to 
4.4  mm.  (about  fourteen  to  seventeen  hundredths  of  an 
inch)  in  width,  or  about  the  same  width  as  the  following 
segments  without  the  lateral  tubercles.  The  ground  color 
is  cream- white,  and  there  is  a  vertical,  velvety-black  stripe 
on  each  side  of  the  clypeus,  outside  and  above  which,  the 
surface  is  sprinkled  more  or  less  thickly  with  velvety-black 
dots,  which  are  more  or  less  confluent.  The  labram  and 
mandibles  are  of  a  watery,  whitish  color,  and  the  mouth 
parts  beneath  are  dull  reddish.  Scattered  over  the  surface 
are  numerous  pale-yellow  setaceous  hairs,  varying  in  length 
from  the  width  of  the  head  to  half  that  length.  The  upper 
surface  of  the  body  is  cream- white,  marked  with  black  in 
minute,  irregularly  formed  spots,  giving  a  general  dark-gray 
color,  but  leaving  the  dorsal  line  of  a  lighter  color.  The 
subdorsal  tubercles,  on  segments  two  to  six  inclusive,  are 
blue,  and  those  on  segments  seven  to  twelve  inclusive,  are 
red.  All  the  tubercles  and  retractile  tubercles  are  of  the 
same  form,  and  arranged  the  same  as  in  the  last  two  stages ; 
the  spines  and  hairs  are  also  like  those  in  the  preceding 
stage.  The  fleshy,  retractile  tubercles  on  the  dorsum  of 


304  THE  GYPSY  MOTH. 

the  tenth  and  eleventh  segments  usually  have  a  convex  cap 
of  hardened  reddish  fluid,  which  may  be  removed  with  the 
point  of  a  needle,  and  beneath  which  the  tubercle  is  hollow 
to  the  depth  of  three  or  four  mm.,  and  filled  with  a  reddish 
fluid,  which  has  an  agreeable  odor,  but  I  am  not  able  to  state 
what  it  is  like. 

Sixth  Larval  Stage.  —  Length,  30  mm.  (about  one  and 
eighteen  hundredths  inches),  immediately  after  molting. 
The  head  is  from  5.5  to  6  mm.  (about  twenty-two  hun- 
dredths of  an  inch)  in  width,  dull  or  yellowish  white,  and 
more  or  less  mottled  with  black  or  brown  over  the  top  and 
sides,  with  a  vertical  black  or  brown  stripe  on  each  side  of 
the  clypeus.  There  is  a  great  variation  in  the  ground  color, 
and  also  in  the  amount  of  black  or  brown  on  the  surface  of 
the  head.  Fine  yellow  hairs  are  scattered  over  the  surface, 
and  the  color  and  markings  are  as  in  the  preceding  stage. 

Seventh  Larval  Stage. — Length,  from  35  to  40  mm. 
There  is  no  marked  difference  in  appearance,  in  this  stage, 
from  the  preceding,  except  in  size,  and  all  caterpillars  that 
we  have  bred  to  this  stage  have  transformed  into  female 
moths.  Only  a  comparatively  small  proportion  of  the  cater- 
pillars reach  this  stage  before  pupating. 

First  and  Last  Appearance  of  Larvae. 
The  newly  hatched  caterpillars  of  the  gypsy  moth  have 
been  found  in  the  field  as  early  as  April  20,  and  as  late  as 
June  17.  In  the  summer  of  1893,  Mr.  H.  N.  Reid  found  a 
caterpillar  which  did  not  begin  to  pupate  until  September  6. 
The  feeding  period  of  the  caterpillar  generally  extends  from 
the  first  of  May,  to  about  the  middle  of  July,  but  varies 
somewhat  with  the  season,  and,  in  a  less  degree,  with  the 
locality  of  the  colony,  those  near  the  sea-shore  being  some- 
what slower  in  development  than  those  farther  inland. 

Molts. 

In  the  latter  part  of  the  winter  of  1893,  Miss  Carrie  Gor- 
don, one  of  the  assistants  at  the  Maiden  office,  observed  the 
molts  of  several  caterpillars  of  the  gypsy  moth,  taken  from 
egg-clusters  which  had  been  kept  in  a  warm  room,  and  thus 


MOLTING.  305 

caused  to  hatch  earlier  than  they  otherwise  would  have  done. 
The  caterpillars  were  fed  on  the  leaves  of  lettuce,  and  four 
of  them  completed  their  transformations, — two  males  and 
two  females,  —  while  three  more  died  in  pupating.  The 
males  molted  five  times  and  the  females  six  times.  Wishing 
to  determine  whether  there  would  be  any  difference  between 
these  caterpillars,  hatched  out  of  season,  and  those  reared 
under  normal  conditions,  twelve  newly  hatched  caterpillars 
of  the  gypsy  moth,  each  in  a  separate  box,  were  given  to 
Miss  Rose  Davis,  one  of  my  assistants,  early  in  May,  1893. 
These  were  fed  on  apple  leaves,  and  each  molt  carefully 
noted.  Of  this  lot,  seven  females  molted  five  times,  one 
female  molted  four  times  and  four  males  molted  four  times. 
As  these  results  differed  so  materially  from  those  of  Miss 
Gordon,  I  took  fifty-five  newly  hatched  caterpillars  in  May, 
1894,  fed  each  on  apple  leaves,  in  a  separate  box,  and  care- 
fully observed  the  molts  myself.  Fifty-two  of  these  cater- 
pillars completed  their  transformations,  with  the  following 
results:  one  female  molted  six  times,  twenty-nine  females 
molted  five  times  and  nine  females  molted  four  times ;  seven 
males  molted  five  times  and  six  males  molted  four  times. 
These  results  showed  that  in  all  probability  no  mistakes 
were  made  by  the  other  observers,  and  also  that  the  process 
of  forcing  the  caterpillars  makes  no  difference  in  the  number 
of  molts,  though  the  small  number  carried  through  by  Miss 
Gordon  fails  to  make  this  point  as  conclusive  as  might  be 
desired. 

The  time  between  the  hatching  of  the  eggs,  which  occurred 
Feb.  3,  1893,  and  the  first  molt,  and  also  between  the 
remaining  molts,  is  as  follows,  according  to  Miss  Gordon's 
observations :  — 

From  the  time  of  hatching  till  the  first  molt,  6  days. 
From  the  time  of  the  first  till  the  second  molt,  7,  8  and  9  days. 
From  the  time  of  the  second  till  the  third  molt,  6  and  7  days. 
From  the  time  of  the  third  till  the  fourth  molt,  5,  6  and  7  days. 
From  the  time  of  the  fourth  till  the  fifth  molt,  6,  7  and  8  days. 
From  the  time  of  the  fifth  till  the  sixth  molt,  8  days. 

According  to  Miss  Davis'  observations,  the  time  between 
the  hatching  of  the  eggs,  which  occurred  May  7  and  8,  1893, 


306 


THE  GYPSY  MOTH. 


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MOLTING. 


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308  THE   GYPSY  MOTH. 

and  the  first  molt,  and  also  between  the  remaining  molts,  is 
as  follows :  — 

From  the  time  of  hatching  till  the  first  molt,  8,  9,  10  and  11 
days. 

From  the  time  of  the  first  till  the  second  molt,  7  and  8  days. 
From  the  time  of  the  second  till  the  third  molt,  7  and  8  days. 
From  the  time  of  the  third  till  the  fourth  molt,  6,  7  and  8  days. 
From  the  time  of  the  fourth  till  the  fifth  molt,  7,  8  and  9  days. 

According  to  my  own  observations,  the  time  between  the 
hatching  of  the  eggs,  which  occurred  April  28  and  29,  1894, 
and  the  first  molt,  and  also  between  the  remaining  molts,  is 
as  follows :  — 

From  the  time  of  hatching  till  the  first  molt,  9,  10  and  11  days. 
From  the  time  of  the  first  till  the  second  molt,  11  days. 
From  the  time  of  the  second  till  the  third  molt,  5,  6  and  7  days. 
From  the  time  of  the  third  till  the  fourth  molt,  10  and  11  days. 
From  the  time  of  the  fourth  till  the  fifth  molt,  8,  9  and  10  days. 
From  the  time  of  the  fifth  till  the  sixth  molt,  13  days. 

The  Process  of  Molting. 

When  preparing  to  molt  the  young  caterpillars  remain 
quiet  for  twenty-four  hours  or  more.  The  head  is  withdrawn 
from  the  old  head  covering,  giving  the  caterpillar  the  appear- 
ance of  having  a  very  small  head.  The  skin  behind  the  head 
covering  is  ruptured,  and  the  caterpillar  crawls  out  of  it,  the 
whole  process  occupying  not  more  than  two  minutes.  Imme- 
diately after  molting  the  long  hairs  of  the  body  are  curled  up 
considerably,  but  gradually  straighten  out  in  about  an  hour. 
At  intervals  of  about  five  minutes  the  caterpillar  twists  about, 
bringing  the  head  to  the  right  and  left  and  upwards  and 
backwards,  nearly  to  the  posterior  end  of  the  body,  as  if 
stretching  itself  or  trying  its  muscles.  The  head  grows  per- 
ceptibly darker,  even  within  an  hour  from  the  time  of  molt- 
ing, and  in  a  few  hours  the  head  becomes  black  and  shining 
and  the  caterpillar  commences  feeding. 

The  approach  of  the  molting  period,  in  the  later  molts,  is 
indicated  by  the  development  of  a  light-colored  area,  which 
forms  behind  the  head  during  three  or  four  days  preceding 


PEOCESS  OF  MOLTING.  309 

molting.  This  area,  which  is  but  a  narrow  transverse  line  at 
first,  gradually  widens  and  extends  down  each  side  of  the 
posterior  margin  of  the  head.  It  is  widest  on  the  dorsal  line, 
and  is  formed  by  the  separation  and  projection  forward  of 
the  old  chitinous  covering  of  the  head,  while  below  and 
beneath,  the  new  light-colored  head  covering  becomes  visi- 
ble. The  light-colored  area  is  apparently  the  top  of  the  head 
drawn  back  from  the  old  covering,  and  protected  by  the 
tightly  stretched  integument  of  the  annulation. 

The  caterpillar  stops  feeding  usually  from  twenty-four  to 
forty-eight  hours  before  molting,  and  rests  quietly  except  for 
occasional  spasmodic  twistings  of  the  body.  When  the  time 
for  molting  arrives,  the  integument  splits  on  the  ventral  part 
of  the  annulation  between  the  head  and  second  segment  and 
partly  up  the  sides.  The  caterpillar  clings  by  means  of  its 
pro  legs  to  the  surface  on  which  it  rests.  It  elevates  the 
middle  segments,  depresses  segments  four  and  five  and  ele- 
vates the  head  and  segments  two  and  three.  Its  contortions, 
at  this  stage,  somewhat  resemble  the  travelling  movements 
of  a  geometrid  caterpillar,  and,  as  the  band  over  the  light- 
colored  area  behind  the  head  is  very  tenacious,  the  caterpillar 
bends  itself  nearly  double ;  the  feet  are  then  withdrawn  by 
a  series  of  successive  movements;  with  a  few  more  con- 
tortions of  the  body  sufficient  force  is  developed  to  burst  the 
band  in  the  rear  of  the  head,  and  the  dorsal  surface  of  the 
thoracic  segments  is  molted.  This  stage  requires  about  five 
minutes  from  the  first  separation  of  the  integument.  The 
head  covering  generally  remains  attached. 

By  alternately  contracting  and  expanding,  the  remaining 
segments  are  molted  one  after  another.  The  last  three  seg- 
ments are  generally  molted  in  rapid  succession,  and  the  molt- 
ing, with  the  exception  of  the  head,  is  completed  in  about 
fifteen  minutes.  After  resting  a  few  minutes  the  caterpillar 
begins  to  rid  itself  of  the  firm  head  covering.  This  is  done 
by  bending  down  the  anterior  segments,  and  then  rubbing  the 
top,  front  and  sides  of  the  head  upon  the  surface  to  which  the 
caterpillar  clings.  Finally,  the  top  of  the  head  covering  is 
loosened  and  pushed  off.  This  process  of  molting  the  head 
requires  from  fifteen  minutes  to  half  an  hour,  and  the  whole 
process  is  completed  in  less  than  an  hour.  After  molting 


310  THE  GYPSY  MOTH. 

the  caterpillar  raises  its  head  and  swings  it  from  side  to  side, 
resting  at  intervals,  and  begins  feeding  in  about  twenty-four 
hours.  The  increase  in  the  size  of  the  body  over  that  of  the 
preceding  molt,  is  more  plainly  noticed  after  the  caterpillar 
has  taken  its  first  meal,  but  the  increased  size  of  the  head  is 
apparent  at  once.  When  first  emerged  from  the  molted  skin 
the  head  is  nearly  cream- white,  with  faint  darker  markings, 
and  all  the  colors  of  the  body  are  light,  but  after  a  few 
hours  they  darken  to  the  normal  shades.  The  dorsal  retrac- 
tile tubercles  are  very  prominent  immediately  after  molting, 
but  regain  their  normal  size  in  a  short  time. 

Caterpillars  attracted  to  Light. 

When  caterpillars  hatch  in  hollow  trees  or  other  dark 
places,  they  invariably  find  their  way  out  in  a  short  time, 
being  attracted,  as  it  is  supposed,  towards  the  light.  To 
determine  how  strongly  the  light  influenced  them  in  their 
movements,  May  6,  1895,  twenty-five  newly  hatched  cater- 
pillars were  placed  in  small  pasteboard  boxes  which  had  a 
small  hole  in  each  end.  One  end  of  each  box  was  placed  in 
the  bright  sunlight,  while  the  other  end  was  shaded.  In 
an  hour  and  a  half  all  the  caterpillars  had  emerged  through 
the  holes  in  the  ends  exposed  to  the  sun. 

Distance  Young  Caterpillars  are  able  to  Travel. 
For  the  purpose  of  ascertaining  how  far  from  the  egg- 
cluster  a  newly  hatched  caterpillar  can  travel  without  feed- 
ing, seven  were  placed  on  a  large  sheet  of  white  paper  on  a 
table.  Their  movements  were  traced  by  following  them 
with  the  point  of  a  pencil  on  the  paper  as  they  crawled, 
and  these  lines  were  carefully  measured  after  the  death  of 
the  caterpillars.  In  their  movements  it  was  observed  that 
they  showed  a  strong  tendency  to  crawl  towards  the  window 
during  the  day,  and  towards  the  light  of  the  lamp  during  the 
night;  but  in  no  case  were  they  observed  to  be  attracted 
towards  food,  however  near  it  was  placed,  provided  it  did 
not  touch.their  hairs.  The  distance  travelled  by  each  cater- 
pillar before  it  died  was  as  follows:  No.  1  travelled  9(H 
feet;  No.  2,  93  feet;  No.  3,  143  feet;  No.  4,  85  feet;  No, 
5,  36  feet;  No.  6,  46|  feet;  and  No.  7,  144  feet;  aver- 


CATERPILLAR  TRAPS.  311 

age,  about  91  feet.  These  observations  have  a  bearing  on 
the  question  of  how  far  the  trees  around  a  colony  should  be 
burlapped. 

Caterpillar  Traps. 

In  the  summer  of  1895,  at  the  suggestion  of  Mr.  For- 
bush,  several  attempts  were  made  to  capture  the  caterpil- 
lars of  the  gypsy  moth  by  means  of  traps,  constructed  with 
reference  to  their  habit  of  seeking  out  cracks,  crevices,  etc., 
for  shelter  during  the  day.  Different  styles  of  traps  were  pre- 
pared, all  made  with  small  openings,  closed  by  a  fringe  of 
hair-cloth  or  felt,  through  which  the  insect  might  enter  but 
could  not  return.  These  traps  were  attached  to  the  trunks 
of  badly  infested  trees  ;  and,  while  they  caught  and  retained 
a  small  number  of  caterpillars,  as  a  whole  they  were  not  a 
success. 

When  a  number  of  old  tin  cans  are  placed  along  an 
infested  hedge  or  wall,  at  the  time  the  caterpillars  are 
pupating,  it  has  been  found  that  they  will  enter  them  in 
large  numbers  and  pupate.  Females,  emerging  in  these 
cans,  deposit  their  eggs  there  ;  and  by  frequent  examination 
of  the  cans  a  large  number  of  pupae  and  egg-clusters  can  be 
destroyed. 

FEEDING  HABITS. 

In  general,  it  may  be  said  that  the  gypsy  moth  caterpillar 
is  almost  omnivorous  so  far  as  foliage  is  concerned,  and  its 
ability  to  adapt  itself  to  nearly  every  food  plant  is  one  of 
the  chief  obstacles  to  its  extermination.  For  this  reason, 
also,  it  is  capable  of  committing  far  greater  depredations 
than  any  of  our  common  native  insects.  A  list  of  food 
plants  attacked  by  the  gypsy  moth  is  given  on  succeeding 
pages,  and,  since  the  ravages  of  the  insect  on  fruit  and 
forest  trees  have  been  so  fully  described  in  Part  I.  of  this 
report,  we  pass  to  a  more  detailed  account  of  the  feeding 
habits.  The  feeding  habits  of  caterpillars  of  different  ages 
are  shown  on  Plate  40. 

Time  and  Manner  of  Feeding. 

To  determine  the  time  and  manner  of  feeding  of  the  cater- 
pillars, a  series  of  observations  was  made  by  Mr.  Minott  in 


312  THE  GYPSY  MOTH. 

1893,  and  repeated  by  Mr.  Kirkland  in  1894.  Many  obser- 
vations had  been  made  by  different  members  of  the  force, 
but  none  were  so  extensive  or  complete  as  those  made  by 
these  gentlemen,  yet  all  agreed  more  or  less  in  regard  to 
the  habits.  To  enable  one  to  make  observations  on  cater- 
pillars, on  trees  in  the  field  or  forest,  it  was  necessary  to 
have  some  system  of  marking ;  and  for  this  purpose  water- 
colors  were  found  to  be  excellent,  and  in  no  way  injured  the 
insects ;  though,  in  the  case  of  caterpillars  which  were  to  be 
continuously  observed  during  the  entire  larval  stage,  it  was, 
of  course,  necessary  to  reapply  the  color  after  each  molt. 
Several  different  colors  were  used,  especially  those  which 
contrasted  strongly  with  the  ground  color  of  the  caterpil- 
lars. 

From  these  observations  it  appears  that  the  caterpillars 
remain  on  the  egg-cluster,  after  hatching,  from  one  to  five 
or  more  days,  according  to  the  weather,  when  they  wander 
off  to  the  leaves  and  commence  feeding.  The  first  food 
is  the  leaf  hairs,  and,  unless  one  observes  very  carefully, 
he  might  suppose  that  they  do  not  feed  until  they  are  four 
or  five  days  old ;  from  this  time  on,  however,  one  can  see 
where  they  have  eaten  the  tissues,  making  small  holes 
through  the  leaf,  though  occasionally  they  eat  from  the 
edge  ;  but  they  are  extremely  irregular  in  their  manner  of 
feeding.  Between  the  third  and  fourth  molts  their  method 
of  feeding  is  about  equally  divided  between  eating  holes 
through  the  leaf  and  eating  along  the  edge  (Plates  40  and 
44).  From  the  fourth  molt  till  they  are  ready  to  pupate, 
they  eat  almost  entirely  from  the  edge  of  the  leaf,  though 
there  are  occasional  exceptions  to  this. 

Mr.  Kirkland's  observations  on  full-grown  caterpillars 
were  made  on  the  nights  of  July  7,  8  and  9,  1894.  A  me- 
dium-sized infested  elm  tree  was  selected,  and  all  small  twigs 
and  branches  that  might  interfere  were  removed.  A  band  of 
burlap  had  been  put  around  the  trunk,  about  four  feet  from 
the  ground.  Twenty  caterpillars,  some  partly  and  some 
fully  grown,  were  under  the  burlap.  Eight  of  these  cater- 
pillars were  marked  with  water-colors,  in  such  a  manner  that 
they  could  be  distinguished  from  each  other  as  well  as  from 
those  not  marked.  The  caterpillars  were  numbered,  and 


PLATE  44.     Oak  leaves  eaten  by  the  caterpillars  of  the  gypsy  moth. 
Taken  from  an  infested  tree,  Saugus,  July,  1894. 


TIME  AND   MANNER  OF  FEEDING.         313 

observations  made  every  ten  minutes,  from  6  o'clock  in  the 
afternoon  till  5  the  next  morning.  At  7.30  P.M.,  caterpillar 
No.  4  began  to  grow  uneasy,  and  moved  about  under  the  bur- 
lap or  on  the  trunk  below  it.  At  8.20  the  first  one,  No.  2, 
started  up  the  tree  from  the  burlap,  and  soon  all  the  rest 
were  on  the  move.  Some  of  the  caterpillars,  after  climbing 
up  the  trunk  several  feet,  descended  for  a  short  distance  and 
then  ascended  again  ;  and  they  often  stopped  to  rest  on  their 
way  up  or  down  the  tree  trunk.  At  9.50  No.  3  had  reached 
the  leaves,  sixteen  feet  from  the  burlap,  and  begun  feeding. 
Others  reached  the  leaves  later,  and  fed  during  the  night 
with  intervals  of  rest.  At  about  3  A.M.  they  ceased  feeding 
and  descended  the  trunk,  and  at  4.25  all  were  at  rest  under 
the  burlap  or  in  crevices  in  the  bark.  One  caterpillar  about 
to  molt  and  one  about  to  pupate  remained  quietly  under  the 
burlap  all  night.  It  was  further  observed  that  the  smaller 
caterpillars,  as  a  rule,  fed  on  the  lower  branches,  while  many 
of  the  larger  ones  went  to  the  extreme  tips  of  the  upper 
limbs. 

Mr.  Minott's  observations  were  made  on  the  nights  of 
July  26,  27,  28  and  29,  1893;  and  the  results  were  sub- 
stantially the  same  as  in  Mr.  Kirkland's  observations,  except 
that  the  caterpillars  started  from  their  places  of  concealment 
to  ascend  the  trees  a  little  earlier  in  the  evening.  The 
observations  of  Mr.  Kirkland,  on  a  single  caterpillar,  will 
illustrate  fairly  well  the  operations  of  the  insect  during  the 
night,  though  others  varied  slightly  in  their  work :  — 

P.M. 

7.40.     Caterpillar  came  out  from  under  the  burlap  and  began 

moving  up  the  tree. 

7.50.     Ascended  the  trunk,  twelve  feet  from  the  burlap. 
8.00.     Reached  a  leaf  fifteen  feet  from  burlap  and  commenced 

feeding. 

8.10.     Still  feeding. 
8.20.     Had  three  feeding  spells  between  8  and  8.15,  with  short 

rests  between. 
8.30.     Feeding. 
8.40.     Moving. 
8.50.     Feeding. 
9.00.     Feeding. 


314  THE   GYPSY  MOTH. 

P.M. 

9.10.  Feeding.  It  began  at  the  base  of  the  leaf,  clasping  the 
petiole  and  twig  with  feet  and  prolegs,  eating  the  base 
of  the  leaf  close  to  the  midrib,  then,  raising  its  head, 
worked  out  toward  the  margin  of  the  leaf,  making  a 
crescent-shaped  cut,  then  started  from  the  midrib 
again. 

9.20.     Feeding. 

9.30.     Eesting,  after  having  eaten  steadily  twenty-five  minutes. 

9.40.     Feeding    (began   at   9.31).     The   caterpillar  then    fed 

steadily  until  11  P.M. 

11.00.  Resting  a  few  seconds,  after  feeding  one  and  one-half 
hours. 

A.M. 

12.10.  Feeding.  Has  fed  continuously  since  11. 10;  has  eaten 
the  whole  of  one  side  of  a  leaf  and  is  now  working 
upon  the  tip. 

12.20.     Feeding  upon  the  tip  of  the  remaining  half  of  the  leaf. 
It  begins  at  the  midrib,  actually 'eating  it,  then  takes 
a  strip   square   across   the  leaf   to  the  margin,  then 
begins   eating   again   at   the   midrib.     Sometimes    it 
reverses  this  movement,  and  feeds  from  the  margin 
to  the  midrib. 
12.30.     Feeding. 
12.40.     Feeding. 

12.50.     Left  the  remains  of    its  leaf,    having   eaten   nearly  all 

through  it,  and  started  at  once  upon  the  second.     The 

caterpillar   then   fed   without  interruption  until  3.20 

A.M. 

3.20.     Stopped  feeding,  crawled  out   to  the  end  of  the  twig, 

turned  back  and  crawled  down  the  main  branch. 
3.30.     Slowly  descending  (daylight  approaching). 
3.40.     Descending. 

3.50.     Descending,  about  four  feet  above  the  burlap. 
4.00.     Descending. 
4.10.     Crossed  the  burlap,  ci'awled  under  it,  and  at  once  became 

quiet. 
Weather  during  the  night,  fair,  cool  and  starlight. 

Summary. 

Detailed   observations   made   on   twenty-five    caterpillars 
may  be  summarized  as  follows  :  — 


PLATE  45.     Hornbeam  and  other  trees  stripped  by  the  caterpillars 
of  the  gypsy  moth,  Swampscott,  1891. 


AMOUNT  OF  FOOD.  315 

1.  The  large  caterpillars  leave  the  burlap  or  other  places 
of  concealment  for  their  places  of  feeding  between  7  and  8 
o'clock  in  the  evening,  or  sometimes  a  little  later. 

2.  They   proceed   by   easy   stages,    resting    frequently, 
from  their  places  of  concealment  to  the  places  of  feeding, 
though  some  of  them  wander  up  and  down  the  trees  more 
or  less. 

3.  When  the  distance  is  short,  they  proceed  directly  to 
the  leaves  and  begin  feeding  immediately. 

4.  They  feed  and  rest  alternately,  at  frequent  intervals 
during  the  night. 

5.  As  a  rule,  they   go  to  the  same  feeding   place  each 
night  and  return  to  the  same  place  of  concealment,  though 
they   will   accustom   themselves   to   a   new   feeding    place, 
especially  in  the  younger  stages. 

6.  They   cease   feeding   at   daylight    (between  3  and  4 
o'clock  in  the  morning),  but  when  it  is  cloudy  they  feed 
later.     It  would  seem  that   the  first  indication  of  daylight 
is  the  signal   for  them  to   return   to   their  places   of  con- 
cealment. 

Amount  of  Food  consumed  by  Caterpillars. 
To  learn  the  amount  of  food  hungry  caterpillars  of  dif- 
ferent ages  would  consume  in  twenty-four  hours,  the  follow- 
ing experiment  was  made  during  the  summer  of  1895 :  a 
known  quantity  of  food  was  supplied  to  the  caterpillars, 
and  at  the  end  of  a  specified  time  the  remains  of  the  leaves 
were  carefully  soaked  in  water  and  then  measured.  May 
10,  at  4.30  P.M.,  three  caterpillars,  between  the  first  and 
second  molt,  were  placed  in  a  breeding  jar  with  6  square 
inches  of  lettuce  leaf.  At  7.30  A.M.,  May  11,  4  square 
inches  were  added,  making  a  total  of  10  square  inches. 
May  11,  at  7.30  A.M.,  the  refuse  was  removed,  and  equalled 
2  square  inches,  thus  giving  8  square  inches  as  the  amount 
consumed  by  the  three  caterpillars,  or  2^  square  inches  per 
caterpillar  for  twenty-four  hours.  May  10,  at  4.30  P.M., 
three  caterpillars,  between  the  second  and  third  molt,  were 
supplied  with  9  square  inches  of  lettuce  leaf.  The  next 
morning  4  square  inches  were  added,  and  at  1.30  P.M. 


316  THE  GYPSY  MOTH. 

2  square  inches.  The  refuse,  which  was  removed  at  4.30 
P.M.,  measured  3  square  inches,  making  12  square  inches 
which  had  been  eaten  by  the  three  caterpillars,  or  4  square 
inches  per  caterpillar.  May  10,  at  4.30  P.M.,  three  cater- 
pillars, between  the  third  and  fourth  molt,  were  supplied 
with  lettuce  as  follows :  May  10,  at  4.30,  9  square  inches ; 
May  11,  at  7.30,  4  square  inches;  and  at  1.30  P.M.  4  square 
inches :  total,  17  square  inches.  The  refuse  was  removed 
May  11,  and  measured  3  square  inches,  leaving  14  square 
inches  as  the  amount  consumed,  or  4|  square  inches  per 
caterpillar.  Three  caterpillars,  between  the  fourth  and  fifth 
molt,  were  supplied  with  18  square  inches  of  lettuce  at  the 
same  date  and  hour,  and  on  May  11,  at  7.30  A.M.,  9  square 
inches  were  added ;  and  at  1.30P.M.  9  square  inches  more. 
The  refuse,  removed  at  4.30  P.M.,  May  11,  measured  5 
square  inches,  leaving  31  square  inches  the  amount  con- 
sumed by  all,  or  10^  square  inches  per  caterpillar.  June  26, 
three  caterpillars,  between  the  last  molt  and  pupation,  were 
given  20  square  inches  of  lettuce  leaf  at  7  A.M.,  and  at 
5  P.M.,  20  square  inches  more  were  added.  At  7  A.M.,  June 
27,  the  refuse  was  removed  and  soaked  out.  It  then 
measured  5  square  inches,  making  35  square  inches  that  had 
been  eaten  by  the  three  caterpillars,  or  11|  square  inches 
per  caterpillar. 

These  figures  give  evidence  of  the  food  capacity  of  the 
caterpillars,  but  it  should  be  borne  in  mind  that  lettuce  does 
not  offer  so  much  resistance  to  the  jaws  (mandibles)  of  the 
caterpillar  as  do  the  harder  leaves  of  the  apple,  oak  and 
others. 

Food  Plants. 

A  series  of  experiments  was  conducted  during  the  part  of 
the  season  of  1895  that  the  gypsy  moth  was  in  the  caterpillar 
stage,  for  the  purpose  of  determining  so  far  as  possible  all 
the  plants  this  insect  will  feed  upon.  For  this  purpose  col- 
lectors brought  in  specimens  of  all  the  plants  met  with  in  the 
fields  and  forests  of  the  infested  territory.  To  Mr.  H.  L. 
Frost,  a  careful  student  of  botany  as  well  as  entomology, 
was  assigned  the  work  of  determining  these  plants  and  carry- 
ing out  the  details  of  the  experiment.  While  the  plants  were 


FOOD   PLANTS.  317 

still  fresh  they  were  placed  in  eight-ounce  glass  jars,  and  four 
caterpillars,  in  the  fourth  or  fifth  molt,  were  placed  upon  them. 
This  number  was  about  all  that  could  feed  without  crowd- 
ing, and  at  the  same  time  give  appreciable  results  before  the 
plants  wilted.  The  jars  were  covered  at  the  top  with  thin 
cloth,  to  prevent  the  escape  of  the  caterpillars  and  at  the 
same  time  to  allow  ventilation.  They  were  numbered,  and 
the  numbers,  with  the  names  of  the  plants,  were  booked  at 
the  time  the  caterpillars  were  placed  on  the  food,  the  jars 
being  kept  in  a  place  sufficiently  cool  to  prevent  undue  evap- 
oration, but  at  a  temperature  at  which  the  caterpillars  fed 
readily.  Observations  were  made  every  twenty- four  hours, 
and,  if  at  the  end  of  three  days  the  caterpillars  showed  an 
unwillingness  to  feed  on  the  plant,  the  experiment  was  re- 
peated with  a  fresh  stock  of  caterpillars  on  a  fresh  supply  of 
the  same  food.  If  they  did  not  attack  it  at  the  second  trial, 
in  view  of  their  accustomed  readiness  to  feed  on  nearly  all 
plants,  it  was  assumed  that  they  would  not  feed  on  the  plant 
in  question.  The  flora  of  the  region  about  Maiden  is  mari- 
time rather  than  inland,  and  some  of  the  common  plants 
of  the  central  and  western  parts  of  the  State  do  not  occur 
there. 

Attention  is  called  to  the  fact  that  the  caterpillars  of 
the  gypsy  moth  feed  readily  on  common  water  plants, 
such  as  NympJiaza  odorala,  Pontederia  cordata  and  Alisma 
planlago.  Experiments  performed  this  year  proved  that 
some  of  the  caterpillars  will  live  for  several  days  floating 
on  the  water  and  without  food.  These  two  facts  in  connec- 
tion may  help  to  explain  the  distribution  of  this  insect  along 
streams. 

In  the  following  lists  both  the  common  and  scientific 
names  are  given,  as  far  as  possible.  The  nomenclature  is 
that  of  Gray's  "Manual  of  Botany,"  1889,  for  the  wild 
plants,  and  Wood's  "Botany"  of  1889,  for  the  cultivated 
plants.  An  asterisk  before  a  name  denotes  that  the  cater- 
pillars fed  on  the  plant  only  when  forced  to  do  so  by 
starvation.  It  will  be  noticed  that  about  twenty-one  per 
cent,  of  the  plants  in  the  following  list  are  of  economic 
value. 


318 


THE   GYPSY  MOTH. 


Plants  upon  which  the  Gypsy  Moth  Caterpillar  has  been  known  to  feed 
in  Massachusetts. 


Virgin's  bower  (Clematis  Virginiana). 
*Wind  flower  (Anemone  Virginiana). 
White   water    crowfoot    (Ranunculus 

aquatilis,  var.  trichophy llus) . 
Small-flowered  crowfoot   (Ranunculus 

abortivus) . 
Hooked  crowfoot   (Ranunculus  recur- 

vatus) . 
Bulbous  crowfoot  (Ranunculus  bulbo- 

•«*)• 
Wild   columbine  (Aquilegia  Canaden- 

sis). 

Peony  (Pceonia  officinalis). 
Umbrella  tree  (Magnolia  umbrella) . 
"Magnolia  Soulangeana. 
Tulip  tree  (Liriodendron  Tulipifera). 
Siberian  pea  tree  (Caragana  arbor  es- 

cens) . 

Barberry  (Berberis  vulgaris). 
Holly  barberry  (Berberis  Aquifolium). 
White  water  lily  (Nympheea  odorata). 
Pitcher  plant  (Sarracenia  purpurea) . 
Celandine  (Chelidonium  majus). 
Poppy  (Papaver  orientalis). 
*Pale  corydalis  ( Corydalis  glauca) . 
*Sweet  alyssum  (Alyssum  maritimum). 
Horseradish  (Nasturtium  Armoracia). 
Hedge  mustard  ( Sisymbrium  officinale) . 
Black  mustard  (Brassica  nigra). 
Turnip  ( Brassica  rapa,  var.  depressa) . 
Savoy  cabbage  (Brassica  oleracea,  var. 

bullata). 
Shepherd's  purse  (Capsella  Bursa-pas- 

toris). 
Wild  peppergrass   (Lepidium   Virgini- 

cum). 

*Sea  rocket  (Cakile  Americana). 
Radish  (Raphanus  Raphanistrum) . 
Blue  violet  ( Viola  palmata,  var.  cucul- 

lata). 
Primrose-leaved  violet  ( Viola  primula- 

folia). 

Lance-leaved  violet  (Viola  lanceolata). 
Dog  violet  (Viola  canina,  var.  Muhlen- 

bergii) . 

Pansy  ( Viola  tricolor) . 
Carnation  pink    (Dianthus   caryophyl- 

lus). 

•Sweet  William  (Dianthus  barbatus) . 
Bouncing  bet  (Saponaria  officinalis). 
Corncockle  (Lychnis  Githago). 
Common  chickweed  (Stellaria  media). 
Mouse-ear  chickweed  (Cerastium  vul- 

gatum). 


Sand  spurrey  (Buda  rubra). 

Purslane  (Portulaca  oleracea). 

St.    John's-wort    (Hypericum    perfor- 
atum) . 

Marsh  St.  John's-wort  (Elodes  campan- 
ulata). 

Hollyhock  (Altheea  rosea) . 

Common  mallow  (Malva  rotundifolia) . 

Indian  mallow  (Abutilon  vexillarium) . 
•Chinese  hibiscus  (Hibiscus  Rosa-Sinen- 
sis). 

Cotton  plant  (Gossypium  herbaceum). 

Bass  wood  (Tilia  Americana). 

European  linden  ( Tilia  Europ&a) . 

Wild  cranesbill  ( Geranium  maculatum) . 

Geranium  (Geranium  sanguineum). 

Yellow  wood  sorrel  ( Oxalis  corniculata, 
var.  stricta) . 

Nasturtium  (Tropceolum  majus). 

Spotted  touch-me-not  (Impatiens fulva) . 

Fraxinella  (Dictamnus  albus). 
*Shrubby  trefoil  (Ptelea  trifoliata). 
*Lemon  (Citrus  Limonum). 

Tree  of  Heaven  (Ailanthus  glandulo- 
sus). 

Black  alder  (Ilex  vertieillata) . 

Climbing  bittersweet  (Celastrus  scan- 
dens). 

European      spindle-tree      (Euonymus 
Europaus) . 

Grape  ( Vitis  vinifera) . 

Northern  fox  grape  ( Vitis  Labrusca) . 

Virginian  creeper  (Ampelopsis  quinque- 
folia). 

Ampelopsis  veitchii. 

Horse    chestnut    (JEscuhis    Hippocas- 
tanum). 

Red  buckeye  (JEsculus  Pavia). 

Sugar  maple  (Acer  saccharinum) . 

White  maple  (Acer  dasycarpum). 

Cut-leaved  maple    (Acer  dasycarpum, 
var.  Weirii). 

Red  maple  (Acer  rubrum). 

Sycamore   maple    (Acer  Pseudo-Plat- 
anus). 

Box  elder  (Negundo  aceroides). 

Variegated  box  elder  (Negundo  acer- 
oides, var.  variegata) . 

Kceulreuteria  paniculata. 

Stag-horn  sumach  (Rhustyphina). 

Smooth  sumach  (Rhus  glabra). 

Poison  dogwood  (Rhus  venenata). 

Poison  ivy  (Rhus  Toxicodendron). 

Rhus  • 


FOOD  PLANTS. 


319 


Plants  upon  which  the  Gypsy  Moth  Caterpillar  has  been  known  to  feed 
in  Massachusetts  —  Continued. 


Smoke  tree  (Rhus  Cotinus) . 

Milkwort  (Poly gala  poly  gama). 

Wild  indigo  (Baptisia  tinctoria) . 

Yellow  wood  (Cladrastis  lutea). 

Dyer's  green  weed  (Genista  tinctoria). 

Rabbit- foot  clover  (Trifolium  arvense). 

White  clover  (Trifolium  repens). 

Red  clover  (Trifolium pratense) . 

Alsike  clover  (Trifolium  hybridum). 

Yellow  clover  (Trifolium  agrarium). 

Low  hop  clover  ( Trifolium procumbens) . 

False  indigo  (Amorpha  fruticosa) . 

Locust  (Robinia  Pseudacacia). 

Wistaria  (  Wistaria  consequana) . 

Tick  trefoil  (Desmodium  nudiflorum). 

Common  vetch  ( Vicia  sativa) . 

Beach  pea  (Lathyrus  maritimus). 

Ground-nut  (Apios  tuberosa) . 

Scarlet   pole    bean   (Phaseolus   multi- 
form). 

Bush  bean  (Phaseolus  nanus). 

Red  bud  (Cercis  Canadensis). 

Kentucky    coffee    tree    (Gymnocladus 
Canadensis) . 

Honey  locust  (Gleditschia  triacanthos) . 

Chinese  honey  locust  (Gleditschia  Si- 
nensis) . 

Coffee  bean  (Faba  vulgaris). 

Pea  (Pisum  sativum). 

Cercidiphyllum  Japonicum. 

Beach  plum  (Prunus  maritima). 

Wild  red  cherry  (Prunus  Pennsylvan- 
ia). 

Choke  cherry  (Prunus  Virginiana) . 

Wild  black  cherry  (Prunus  serotina). 

Damson  plum  (Prunus  domestica). 

English  cherry  (Prunus  Avium). 

Peach  (Prunus  vulgaris) . 

Purple-leaved  plum  (Prunus  Pissardi). 

Prunus  Davidii. 

Apricot  (Prunus  Armeniaca). 

Japanese  plum  (Prunus  Japonica) . 

Meadow  sweet  (Spircea  salicifolia) . 

Hardback  (Spircea  tomentosa) . 

Spircea  Thunbergii. 

Purple    flowering    raspberry     (Rubus 
odoratus) . 

Dwarf  raspberry  (Rubus  triflorus) . 

Wild  red  raspberry  (Rubus  strigosus). 

Thimbleberry  ( Rubus  occidentalis) . 

High  blackberry  (Rubus  villosus). 

Low  blackberry  (Rubus  Canadensis). 
*Avens  (Geum  macrophyllum). 

Strawberry  (Fragaria  Virginiana). 


*Cinqnefoil  (Potentilla  Norvegica). 

Silvery    cinquefoil   (Potentilla   argen- 
tea). 

Common    cinquefoil    (Potentilla   Can- 
adensis) . 

Shrubby  cinquefoil   (Potentilla  fruti- 
cosa) . 

Agrimony  (Agrimonia  Eupatoria). 

Prairie  rose  (Rosa  setigerd). 

Dwarf  wild  rose  (Rosa  lucida). 

Rose  (Rosa  nitida) . 

Crab  apple  (Pyrus  coronaria). 

Narrow-leaved  crab  apple  (Pyrus  an- 
gustifolia) . 

Choke  berry  (Pyrus  arbutifolia). 

American  mountain  ash  (Pyrus  Amer- 
icana) . 

Pyrus  sambucifolia. 

Pyrus  pinnatifida. 

Pyrus  decata. 

Pear  (Pyrus  communis). 

Apple  (Pyrus  Malus). 

English  hawthorn  (Crateggus  Oxyacan- 
tha). 

Paul's  thorn   (Crat&gus  coccinea,  var. 
Paulii). 

Cockspur  thorn  (Cratagus  Crus-galli). 

Shad  bush  (Amelanchier  Canadensis) . 

Amelanchier  alnifolia. 

Quince  (Cydonia  vulgaris). 

Japan  quince  ( Cydonia  Japonica) . 
*Sweet-scented  shrub  (Calycanthus Jlo- 
ridus). 

Mock  orange  (Philadelphia  coronarius) . 
*Deutzia  gracilis. 

Hydrangea  paniculata. 

Common  red  currant  (Ribes  rubrum). 

Black  currant  (Ribes  nigrum). 

Gooseberry  (Ribes  grossularia) . 

English  gooseberry  (Ribes  Uva-crispa). 

Ditch  stonecrop  (Penthorum  sedoides). 

Garden  orpine  (Sedum  Telephium). 

Witch  hazel  (Bamamelis  Virginiana). 

Sweet  gum  tree  (Liquidambar  Styract- 
flua). 

Swamp    loosestrife   (Decodon    verticil- 
lotus). 

Pomegranate  (Punica  granatum) . 

Great  willow  herb  (Epilobium  angusti- 
folium) . 

Slender   willow  herb   (Epilobium   lin- 
ear e). 

Common  evening  primrose  (CEnothera 
biennis). 


320 


THE   GYPSY  MOTH. 


Plants  upon  which  the  Gypsy  Moth  Caterpillar  has  been  known  to  feed 
in  Massachusetts  —  Continued. 


Evening  primrose  (CEnothera  pumila). 
Ladies'  eardrop  (Fuchsia  coccinea). 
Squash  (Cucurbita  verrucosa). 
Cucumber  (Cucumis  sativus). 
•Parsnip  (Peucedanum  sativum). 
Zizia  aurea. 

Celery  (Apium  graveolens). 
Spotted  cow  bane  (Cicuta  maculata). 
Hercules'  club  (Aralia  spinosa) . 
Wild  sarsaparilla  (Aralia  nudicaulis) . 
Flowering  dogwood  (Cornus  forida) . 
Cornus  mas. 

Common  elder  (Sambucus  Canadensis). 
Cranberry  tree  (Viburnum  Opulus). 
Arrowwood  (Viburnum  acerifolium) . 
Downy  arrowwood  (Viburnum  pubes- 

cens) . 

Arrowwood  (Viburnum  dentatum). 
Viburnum  tomentosum. 
Sweet  viburnum  (  Viburnum  Lentago) . 
Black  haw  (Viburnum  prunifolium) . 
Wayfaring  tree  (Viburnum  Lantana). 
Snowberry    (Symphoricarpus   racemo- 

sus). 
Trumpet  honeysuckle  (Lonicera  sem- 

pervirens) . 

Bush  honeysuckle  (Diervilla  trifida). 
Wiegelia  rosea, 
Button    bush    (Cephalanthus   occiden- 

talis). 

Partridge  berry  (Mitchella  repens) . 
Small  bedstraw  (Galium  trifidum). 
Rough  bedstraw  (Galium  asprellum). 
Joe  pye  weed  (Eupatorium purpureum) . 
Thoroughwort    (Eupatorium  perfolia- 

tum). 

Golden-rod  (Solidago  ruaosa). 
Golden-rod  (Solidago  arguta). 
*Golden-rod  (Solidago  Canadensis). 
Golden-rod  (Solidago  lanceolata). 
Aster  ttndulatus. 
Aster  cordifolius. 
Aster  liKvis. 
Aster  puniceus. 
Aster  miter. 

Horse  weed  (Erigeron  Canadensis}. 
Fleabane  (Erigeron  Philadeipkicus) . 
Elecampane  (Inula  Helenium) . 
Roman  wormwood  (Ambrosia  artemis- 

ieefolia) . 

Cone  flower  (Rudbeckia  hirta). 
Sunflower  (Helianthus  annuus). 
*Helianthu3  decapetalus. 
Artichoke  (Helianthus  tuterosus). 


Beggar  ticks  (Bidens  frondosa) . 

Bur     marigold     (Bidens    chrysanthe- 

moides) . 

May  weed  (Anthemis  Cotula). 
Yarrow  (Achillea  Millefolium) . 
Ox-eye    daisy   (Chrysanthemum    Leu- 

canthemum). 
Chrysanthemum  (Chrysanthemum  Si- 

nense) . 

Tansy  ( Tanacetum  vulgar e) . 
Fireweed  (Erechtites  hieracifolia) . 
Burdock  (Arctium  Lappa). 
Common  thistle  (Cnicus  lanceolatus) . 
Tall  thistle  (Cnicus  altissimus). 
Canada  thistle  ( Cnicus  arvensis) . 
Dwarf  dandelion  (Krigia  Virginica). 
Chicory  (Cichorium  Intybus). 
Fall  dandelion  (Leontodnn  autumnale) . 
Rattlesnake    root    (Prenanthes    altis- 

sima) . 

*White  lettuce  (Prenanthes  alba) . 
Dandelion  (Taraxacum  officinale). 
Lettuce  (Lactuca  satira). 
Common  dahlia  (Dahlia  variabilis). 
French  marigold  ( Tagetes  patula) . 
Indian  tobacco  (Lobelia  injlata). 
Lobelia  spicata. 
Venus'  looking  glass  (Specularia  pcr- 

foliata). 

Dangleberry  (Gaylussacia  frondosa) . 
Black  huckleberry  (Gaylussacia  resin- 

ota). 
Dwarf  blueberry  ( Vaccinium  Pennsyl- 

V'tnicum). 

Low  blueberry  (Vaccinium  vacillans). 
Swamp  blueberry  (Vaccinium  corym- 

bosum). 

Leather  leaf  ( Cassandra  calyculata) . 
Sheep  laurel  (Kalmia  angustifolia) . 
Clammy  azalea  (Rhododendron,  visco- 

»um). 

Rhodora  (Rhododendron  Rhodora). 
Great  laurel  (Rhododendron  maximum), 
Labrador  tea  (Ledum  latifolium). 
Sweet  pepperbush  ( Clethra  alnifolid) . 
Prince's  pine  (Chimaphila  umbellata) . 
Shin  leaf  (Pyrola  elliptica). 
Pyrola  rotundifolia. 
Star  flower  (Trientalis  Americana). 
Steironema  ciliatum. 
Loosestrife  (Lysimachia  quadrifolia). 
Sweet  leaf  (Symplocos  cratcegoides) . 
White  ash  (Fraxinus  Americana}. 
Red  ash  (Fraxinus  pubescent). 


FOOD  PLANTS. 


321 


Plants  upon  which  the  Gypsy  Moth  Caterpillar  has  been  known  to  feed 
in  Massachusetts  —  Continued. 


Blue  ash  (Fraxinus  quadrangulata) . 

Black  ash  (Fraxinus  sambucifolia) . 

European  ash  (Fraxinus  excelsior). 

Fraxinus  Oregona. 

Fraxinus  rhycophylla. 

Fraxinus  Sag- Diana. 

Fringe  tree  ( Chionanthus  Virginica) . 

Privet  (Ligustrum  vulgare). 

Common  lilac  (Syringa  vulgaris). 

Japanese  lilac  (Syringa  Japonica) . 

Forsythia  viridissima. 

Dogbane  (Apocynum  androscemifolium) . 

Swamp  milkweed (Asclepias  incamata) . 

Common  milk  weed  (Asclepias  Cornuti) . 

Poke   milkweed    (Asclepias  phytolac- 

coides) . 

Forget-me-not  (Myosotis  arvensis). 
Heliotrope  ( Heliotr  opium  Peruvianum) . 
Morning  glory  (Ipomcea  purpurea) . 
Dodder  (Cuscuta  Gronovii). 

Bittersweet  (Solanum  Dulcamara). 

Potato  (Solanum  tuber osum). 

Petunia  nyctaginifolia. 

Tomato  (Lycopersicum  esculentum). 

Matrimony  vine  (Lycium  vulgare). 
•Virginia  tobacco  (Nicotiana  Tabacum). 

Nicotiana  longiflora. 

Mullein  (Verbascum  Thapsus). 

Toad  flax  (Linaria  Canadensis). 

Butter  and  eggs  (Linaria  vulgaris). 
•Monkey  flower  (Mimulus  ringens) . 

Water  speedwell  ( Veronica  Anagallis) . 
*Purple  gerardia  (Gerardia purpurea) . 

Trumpet  creeper  (  Tecoma  radicans) . 

Catalpa  (Catalpa  bignonioides) . 
•White  vervain  (Verbena  urticcefolia) . 
•Blue  vervain  ( Verbena  hastata). 

Spearmint  (Mentha  viridis). 

Peppermint  (Mentha  piperita). 

Bugle  weed  ( Lycopus  Virginicus) . 

Catnip  (Nepeta  Cataria). 

Self  heal  (Brunetta  vulgaris). 

Dead  nettle  (Lamium  album) . 

Scarlet  sage  (Salvia  splendens). 

Common  plantain  ( Plantago  major) . 

Seaside  plantain  (Plantago  maritima) . 

Green    amaranth    (Amarantus    retro- 
fexus). 

Pigweed  (Chenopodium  album). 
Coast  blite  (Chenopodium  rubrum). 
Spinach  (Spinacia  oleracea). 
Beet  (Beta  vulgaris) . 
Garget  ( Phytolacca  decandra) . 
Patience  dock  (Rumex  Patientia). 


Swamp  dock  (Rumex  verticillatus). 
Cur  led  dock  (Rumex  crispus) . 
Sheep  sorrel  ( Rumex  Acetosella) . 
Rhubarb  (Rheum  Rhaponticum). 
Coast  knotgrass   (Polygonum   mariti- 

mum). 

Door  weed  (Polygonum  aviculare). 
Polygonum  Pennsylvanicum. 
Water  persicaria  (Polygonum  amphib- 

ium) . 

Polygonum  Careyi. 

Lady's  thumb  (Polygonum  Persicaria). 
Water  pepper  (Polygonum  hydropiper- 

oides) . 

Smart  weed  (Polygonum  Jlydropiper) . 
Arrow-leaved  tear  thumb  (Polygonum 

sagittatum). 

Sassafras  (Sassafras  officinale). 
Oleaster  (Eleeagnus  hortensis). 
Elceagnus  Longipes. 
Elaagnus  umbellata. 
Spurge  (Euphorbia  Cyparissias) . 

Slippery  elm  ( Ulmus  fulvus) . 

White  elm  ( Ulmus  Americana) . 

Cork  elm  ( Ulmus  racemosa) . 

English  elm  ( Ulmus  campestris) . 

Scotch  elm  ( Ulmus  montana) . 

Common  hop  (Humulus  Lupulus). 

Red  mulberry  (Morus  rubra). 

Tartarian  mulberry  (Morus  Tartarica). 

Nettle  ( Urtica  gracilis) . 

Nettle  (Urtica  dioioa). 

India  rubber  tree  (Ficus  elastica). 

Sycamore  (Platanus  occidentalis) . 

Butternut  (Juglans  cinerea). 

Shell-bark  hickory  (Carya  alba). 

White-heart  hickory  ( Carya  tomentosa) . 

Pignut  (Carya porcina) . 

Bayberry  (Myrica  cerifera). 

Sweet  fern  (Myrica  asplenifolia) . 

Black  birch  (Betula  lento). 

Yellow  birch  (Betula  lutea). 

White  birch  ( Betula  populifolia). 

Paper  birch  (Betula papyrif era) . 

River  birch  (Betula  nigra). 

Cut-leaved   birch    (Betula   alba,   var. 
laciniata) . 

Betula  Danurica. 

Speckled  alder  (Alnus  incana) . 

Smooth  alder  (Alnus  serrulata). 

Wild  hazelnut  (  Coryhis  Americana) . 

Hop  hornbeam  ( Ostrya  Virginica) . 

White  oak  ( Quercus  alba) . 

Swamp  white  oak  (Quercus  bicolor). 


322 


THE   GYPSY  MOTH. 


Plants  upon  which  the  Gypsy  Moth  Caterpillar  has  been  known  to  feed 
in  Massachusetts  —  Concluded. 


Red  oak  (Quercus  rubra). 

Scarlet  oak  ( Quercus  coccinea) . 

Black  oak  (Quercus  coccinea,  var.  tinc- 

toria) . 

Pin  oak  ( Quercus  palustris) . 
Scrub  oak  ( Quercus  Hid  folia) . 
Barren  oak  (Quercus  nigra) . 
Chestnut  (Castanea  saliva,  var.  Ameri- 
cana) . 

Chinquapin  (Castanea  pumila) . 
Blue  beech  ( Carpinus  Caroliniana) . 
American  beech  (Fagus  ferruginea) . 
Purple   beech   (Fagus   sylvatica,  var. 

purpurea) . 

Crack  willow  (Salix  fragilis) . 
White  willow  (Salix  alba). 
Weeping  willow  (Salix  Babylonica). 
Heart-leaved  willow  (Salix  cordata). 
White  poplar  (Populus  alba). 
American  aspen  (Populus  tremuloides) . 
Large-toothed  aspen  (Populus  grandi- 

dentata) . 
Balm  of  Gilead  (Populus  balsamifera, 

var.  candicans). 
Black  poplar  (Populus  nigra). 
Lombardy  poplar  (Populus  nigra,  var. 

dilatata) . 

White  pine  (Pinus  Strobus). 
Pitch  pine  (Pinus  rigida) . 
Scotch  pine  (Pinus  sylvestris). 
White  spruce  (Picea  alba). 
Norway  spruce  (Picea  excelsa) . 
Pir  (Abies  balsamea). 
Hemlock  (Tsuga  Canadensis). 
Larch  (Larix  Americana). 
European  larch  (Larix  Europeea). 
Arbor  vitae  ( Thuja  occidentalis) . 
Common  juniper  (Juniperus  communis) . 
Red  cedar  (Juniperus  Virginiana). 
*Ginkgo  (Juniperus  Salisburia  adianti- 

folia). 

Ladies'  tresses  (Spiranthes  gracilis). 
Yellow  fringed  orchis  (Habenaria  cili- 

aris) . 

Lady's  slipper  (Cypripedium  acaule). 
Banana  (Musa  sapientum) . 
Canna  (Canna  Indica). 
Blue  flag  (Iris  versicolor) . 
Blue-eyed  grass  (Sisyrinchium  angusti- 

folium). 

Snowdrop  (Galanthus  nivalis) . 
Carrion  flower  (Smilax  herbacea). 
Common  greenbrier   (Smilax  rotundi- 

folia). 


Day  lily  (Hemerocallis  fulva) . 
Adam's  needle  ( Yucca  filamentosa) . 
Lily  of  the  valley  (  Convallaria  majalis) . 
Solomon's  seal  (Polygonatum  bifiorum). 
Asparagus  {Asparagus  officinalis). 
False  Solomon's  seal  (Smilacina  race- 

mosa) . 

*Maianthemum  Canadense. 
Bellwort  ( Oakesia  sessilifolia) .    • 
Wood  lily  (Lilium  Philadelphicum). 
Wild  yellow  lily  (Lilium  Canadense). 
Tiger  lily  (Lilium  tigrinum). 
Indian  cucumber  root   (Medeola  Vir- 

ginica) . 

Pickerel  weed  ( Pontederia  cordata) . 
Yellow-eyed  grass  (Xyrisflexuosa). 
Common  cat  tail  (Typha  latifolia). 
Bur  reed  (Sparganium  simplex). 
Indian  turnip  (Arisa-ma  triphylhim). 
Arrow  arum  ( Peltandra  undulata) . 
Skunk    cabbage    (Symplocarpus  fceti- 

dus). 
*Sweet  flag  (Acorus  Calamus). 

Phyllodendron  Amurense. 
*Water  plantain  (Alisma  Plantaqo). 

Arrow  head  (Sagittaria  variabilis,  var. 
gracilis) . 

Cotton  grass    (Eriophorum  polystach- 
yon). 

Millet  (Panicum  miliaceum). 

Finger  grass  (Panicum  sanguinale). 
*Barnyard  grass  (Panicum  Crus-galli). 

Herd's  grass,  Timothy  (Phleum  pra- 

tense). 
*Meadow  foxtail  (Alopecurus  pratensis) . 

Common  oat  (Avena  sativa) . 

Eragrostis  pectinacea. 

Low  spear  grass  (Poa  annua). 

Kentucky  blue  grass  (Poa  pratensis) . 

Barley  (Hordetim  vulgare). 

Orchard  grass  (Dactylis  glomerata). 

Quitch  grass  (Agropyrum  repenn). 

Bamboo  (Bambusa  arundinacea). 

Indian  corn  (Zea  Mays). 

Common  horsetail  (Equisetum  arvense). 

Common  brake  (Pteris  aquilina). 
*Spleenwort  (Asplenium  ebeneum). 

Shield  fern  (Aspidium  Novcboracense). 

Sensitive  fern  ( Onoclea  sensibilis) . 

Flowering  fern  (  Osmunda  regalis) . 

Osmunda  Claytoniana. 

Cinnamon  fern  ( Osmunda  cinnamomea) . 
*Ground  pine  (Lycopodium  obscurum). 

Selaginella  apus. 


FOOt>  PLANTS. 


323 


Plants  upon  which  the  Gypsy  Moth  Caterpillar  has  been  found  feeding 
in  the  Field. 


Tulip  tree  (Liriodendron  Tulipifera). 
Barberry  (Berberis  vulgaris) . 
Bass  wood  ( Tilia  Americana) . 
European  linden  (Tilia  Europeea). 
Northern  fox  grape  ( Vitit  Labrusca) . 
Horse  chestnut   (JEsculus  Hippocasta- 

num). 

Sugar  maple  (Acer  saccharinum) . 
White  maple  (Acer  dasycarpum) . 
Cut-leaved  maple  (Acer  dasycarpum, 

var.  Weirii). 

Red  maple  (Acer  rubrum) . 
Staghorn  sumach  (Rhus  typhina). 
Smooth  sumach  (Rhus  glabra) . 
Poison  ivy  (Rhus  toxicodendron) . 
Common  locust  (Robinia  Pseudacacia) . 
Cercidiphyllum  Japonicum. 
Wild  red  cherry  (Prunus  Pennsylvan- 

ica). 

Choke  cherry  (Prunus  Virginiand) . 
Wild  black  cherry  (Prunus  serotind). 
Damson  plum  (Prunus  domestica). 
Purple-leaved  plum  (Prunus  Pissardi). 
Wild  red  raspberry  (Rubus  strigosus) . 
Thimbleberry  (Rubus  occidentalis). 
High  blackberry  (Rubus  villosus) . 
Low  blackberry  (Rubus  Canadensis). 
Strawberry  (Fragaria  Virginiana). 
Rose  (Rosa  nitida) . 
Dwarf  wild  rose  ( Rosa  lucida) . 
Choke  berry  (Pyrus  arbutifolia) . 
American  mountain  ash  (Pyrus  Amer- 
icana) . 

Pear  (Pyrus  communis). 
Apple  (Pyrus  Malus). 
Paul's  thorn  (Cratcegus  coccinea,  var. 

Paulii). 

Shad  bush  (Amelanchier  Canadensis) . 
Quince  ( Cydonia  vulgaris) . 
Arrow  wood  (  Viburnum  acerifolium) . 
Ox-eye   daisy    (Chrysanthemum   Leu- 

eanthemum) . 

Burdock  (Arctium  Lappa). 
Dangleberry  (Gaylussacia frondosa) . 
Low  blueberry  (Vaccinium  vaciUans). 
Swamp  blueberry  (Vaccinium  corym- 

bosum). 


Clammy  azalea   (Rhododendron  vitco* 

mm). 

White  ash  (Fraxinus  Americana). 
Common  lilac  (Syringa  vulgaris). 
Bittersweet  (Solanum  Dulcamara). 
Mullein  (Verbascum  Thapsus). 
Slippery  elm  ( Ulmus  fulvd) . 
White  elm  (Ulmus  Americana). 
English  elm  (Ulmus  campestris). 
Sycamore  (Platanus  occidentalis). 
Butternut  (Juglans  cinerea). 
Shell-back  hickory  (Gary a  alba). 
White-heart  hickory  ( Carya  tomentosa) . 
Pignut  ( Carya porcina). 
Bayberry-(3fynca  cerifera). 
American  white  birch  (Betula  populi- 


Paper  birch  (Betula  papyrif era) . 

River  birch  (Betula  nigra) . 

Cut-leaved  birch  (Betula  alba,  var. 
laciniatd) . 

Smooth  alder  (Alnus  semilata). 

Wild  hazel  nut  (Corylus  Americana). 

White  oak  (Quercus  alba). 

Swamp  white  oak  (Quercus  bicolor). 

Red  oak  (Quercus  rvbra). 

Scrub  oak  ( Quercus  ilicifolia) . 

Chestnut  (Castanea  sativa,  var.  Ameri- 
cana) . 

Blue  beech  (Carpinus  Caroliniana) . 

American  beech  (Fagusferruginea). 

Purple  beech  (Fagus  sylvatica,  var. 
purpurea) . 

White  willow  (Salix  alba). 

Weeping  willow  (Salix  Babylonica). 

American  aspen  (Populus  tremuloides) . 

Balm  of  Gilead  (Populus  balsamifera, 
Tar.  candicans). 

White  pine  (Pinus  Strobus). 

Pitch  pine  (Pinut  rigida). 

Common  greenbrier  (Smilax  rotundi 
folia). 

False  Solomon's  seal  (Smilacina  race- 
mosa) . 

Kentucky  blue  grass  (Poa  pratensis) . 

Common  brake  (Pteris  aquilina). 


Plants  upon  which  the  Gypsy  Moth  Caterpillar  did  not  feed. 

Red   baneberry    (Acteea   tpicata,  var 

rubra). 
Rocket  larkspur  (Delphinium  Ajacis). 


Bee  larkspur  (Delphinium  elatum). 
Great-flowered    larkspur   (Delphinium 
grandiflorum) . 


324 


THE   GYPSY  MOTH. 


Plants  upon  which  the  Gypsy  Moth  Caterpillar  did  not  feed  —  Concluded- 


Winter  cress  (Barbarea  vulgaris) . 
Balsamine  (Impatient  balsamina) . 
Myrtle  (Myrtus  communis) . 
Bur  cucumber  (Sicyos  angulatus). 
Everlasting    (Antennaria    plantagini- 

folia). 
Common  everlasting  ( Gnaphalium  poly- 

cephalum) . 
Common  mugwori(Artemisia  vulgaris) . 


Blue  bottle  (Centaurea  Cyanus). 
Rattlesnake  weed  (Hieracium  renosum) . 
Indian  pipe  (Monotropa  uni/tora). 
Red  pepper  (Capsicum  annuum). 
Ground  hemlock  ( Taxus  Canadensis) . 
Pogonia  ophioglossoides. 
Ground  pine   (Lycopodium  complana- 

tum). 
Marsilia  quadrifotta. 


Cotton  as  a  Food  Plant. 

The  question  was  raised  whether  the  gypsy  moth  would 
prove  destructive  to  the  cotton  plant  in  the  South,  should  it 
by  any  means  escape  from  its  present  locality  and  become  dis- 
tributed in  the  cotton  States.  To  decide  this  question,  cotton 
seeds  were  planted  and  two  small  plants  were  raised.  When 
one  of  these  was  about  two  inches  high,  gypsy  caterpillars 
were  placed  on  it,  and  they  devoured  not  only  the  leaves  but 
nearly  all  the  stem,  during  a  single  night.  The  second  plant 
died  before  reaching  the  size  desired  for  the  experiment. 

By  correspondence  with  Mr.  F.  B.  Carpenter  of  the  agri- 
cultural experiment  station  at  Raleigh,  N.  C.,  a  dozen  small 
cotton  plants  were  obtained,  which  were  from  two  to  two 
and  a  half  feet  high.  Although  the  plants  were  well  packed, 
they  were  badly  wilted  when  they  arrived.  All  but  two  were 
set  out  in  the  ground  in  different  places,  in  the  hope  that 
some  of  the  varied  soils  would  prove  congenial,  but  unfort- 
unately none  of  them  lived.  The  leaves  of  one  remaining 
plant  were  taken  off  and  put  into  a  jar  with  ten  caterpillars. 
Notwithstanding  the  fact  that  the  leaves  were  badly  wilted, 
the  caterpillars  on  the  second  day  had  eaten  about  one-fourth 
of  them,  but  at  the  end  of  this  day  the  leaves  had  become  so 
dry  that  this  experiment  was  discontinued.  The  remaining 
plant,  having  been  kept  in  water,  had  revived  somewhat,  and 
on  July  22  twenty  caterpillars,  of  the  fifth  molt,  were  placed 
upon  it,  the  base  of  the  plant  being  kept  in  water.  The  cat- 
erpillars at  once  began  feeding  heartily  on  the  plant,  appear- 
ing to  prefer  the  fresh  leaves  at  the  top  to  the  lower  wilted 
ones.  They  continued  to  feed  till  July  25,  at  which  time 
they  had  devoured  the  greater  part  of  the  plant,  having  eaten 
leaves,  tender  petioles  and  half- developed  boll.  From  this 


PLATE  46.     Oak  branch  attacked  by  gypsy  moth  caterpillars, 
Saugus,  July,  1894. 


EUROPEAN  FOOD-PLANTS. 


325 


experiment  it  seems  evident  that,  if  they  were  numerous  in 
a  Southern  cotton  field,  they  might  prove  quite  as  destruc- 
tive as  the  cotton  worm  (A2etia  argillacea). 

Plants  upon  which  the  Gypsy  Moth  Caterpillar  has  been  known  to  feed 
in  Europe. 


Cabbage  (Brassica  oleraced) . 

Rock  rose  (  Cistus  Laurifolius) . 

Linden  (Tilia  Europeea). 

Spindle  tree  (Euonymus  verrucosus). 

Sycamore  (Acer  Pseudo-Plantanus) . 

Tartar  maple  (Acer  Tartaricum). 

White  lupine  (Lupinus  albus). 

Maple  (Acer platanus)  and  other  species. 

Sainfoin  (  Onobrychis  sativa) . 

Chinese  wistaria  (Wistaria  Sinensis). 

Pea  vines  (Pisum  sativum). 

Honey  locust  (Gleditschia  triacanthos) . 

Plum  (Prunus  domestica). 

Prune  (Prunus  occidentalis  f) . 

Peach  (Primus  Persica). 

Apricot  (Prunus  Armeniacd). 

Sloe  (Prunus  spinosd). 

English  cherry  (Prunus  Avium). 

Laurel  cherry  (Prunus  Laurocerasus) . 

Black  service  berry  (Prunus padus). 

White  thorn  (Crateegus  Pyracantha). 

Hawthorn  (Cratcegus  Oxyacantha) . 

Quince  (Cydonia  vulgaris) . 

Mountain  ash  (Pyrus  aucuparia) . 

Apple  (Pyrus  malus). 

Pear  (Pyrus  communis) . 

European   medlar  (Mespilus  German- 

ica) . 

Chinese  medlar  (Photinia  serrulata). 
Loqnat  tree  (Eriobotrya  Japonica) . 
Strawberry  (Fragaria  vesca). 
Rose  (Rosa  canina). 
Rose  (Rosa  centifolia). 
Pomegranate  (Punica  granatum) . 
Currant  (Ribes  alpinutri). 
Gooseberry  (Ribes  Uva-crispa). 
Cucumber  (Cucumis  sativus). 
Spotted  hemlock  (Conium  maculatum). 
Water  hemlock  (Cicuta  virosa). 
Lettuce  (Lactuca  sativa) . 
Heath  (Erica  Melaleuca) . 
Heather  (Calluna  vulgaris). 
Azalea,  various  species. 
Pimpernel  (Anagallisarvensist). 


Olive  (  Olea  Europeea) . 

Ash  (Fraxinus  excelsior). 

Rhubarb  (Rheum  Rhaponticum) . 

Elm  (  Ulmus  campestris) . 

Elm  ( Ulmus  effusa) . 

Elm  (Ulmus pedunculata) . 

Elm  (Ulmus  subrosa). 

Fig  (Ficus  Carica). 

Plane  tree  (Platanus  orientalis). 

Walnut  (Juglans  nigra). 

Cork  oak  ( Quercus  suber) . 

Holm  oak  (Quercus  Ilex). 

Winter  oak  ( Quercus  pedunculata,  var. 
tardiflora) . 

Oak  (Quercus  pubescens)  and  other 
species. 

Chestnut  ( Castanea  vesca) . 

Beech  (Fagus  sylvaticus) . 

Hazel-nut  (Corylus  Avellana). 

Hornbeam  (Carpinus  betulus). 

Hornbeam  ( Carpinus  orientalis) . 

Sweet  gale  (Myrica  gale) . 

Birch  (Betula  alba)  and  other  species. 

Alder  (Alnus  glutinosa). 

Speckled  alder  (Alnus  incana) . 

Osier  willow  (Salix  viminalis). 

White  willow  (Salix  alba). 

Brittle  willow  (Salix  fragilis) . 

Poplar  willow  (Populus  nigra) . 

Aspen  (Populus  tremula). 

Willow  (Populus  alba)  and  other  spe- 
cies. 

Fir  (Pinus  Abies). 

Scotch  fir  (Pinus  sylvestris) . 

Pine  (Pinus  Picea). 

Larch  (Larix  Europeea). 

Spruce  (Abies  excelsa) . 

Arbor  vitse  (Thuja  occidentalis). 

Savin  (Juniperus  Sabina). 

Cypress  (Cupressus  sempervirens). 

Lime  tree  (Cupressus  Limetta). 

Yew  (Taxus  baccata). 

Grass,  various  species. 

Grain. 


An  Experiment  in  Starving  Caterpillars. 
March  20,  1895,  twenty-five  newly  hatched  caterpillars, 
and  also  the  same  number  from  each  of  the  first,  second  and 


326 


THE  GYPSY  MOTH. 


third  molts,  were  placed  in  corked  vials  without  food,  and 
kept  in  a  normal  temperature,  in  order  to  see  how  long  they 
would  live  under  such  conditions.  Observations  were  made 
on  them  at  intervals  of  twenty-four  hours.  The  following 
table  gives  the  number  of  caterpillars  dying  on  the  specified 
dates : — 


i- 

i* 

|a 

!* 

1* 

J5S 

!< 

§£ 

S§ 
8 

§S 

£ 

| 

Just  hatched,  . 

- 

~ 

5 

8 

12 

- 

- 

- 

- 

- 

25 

First  molt, 

- 

- 

1 

11 

13 

- 

- 

- 

- 

- 

25 

Second  molt,  . 

- 

- 

- 

7 

9 

9 

- 

- 

- 

- 

25 

Third  molt,    . 

- 

- 

- 

9 

7 

3 

l 

3 

- 

2 

25 

This  shows  that  caterpillars  in  the  earlier  stages  will 
readily  live  four  days  without  food ;  that  an  appreciable 
number  of  second-molt  caterpillars  will  live  under  the  same 
conditions  for  five  days,  while  the  third-molt  caterpillars 
may  exist  on  starvation  diet  for  nine  days. 

To  gain  further  knowledge  of  the  period  of  time  it  is 
possible  for  gypsy  moth  caterpillars  to  live  without  food, 
a  number  of  them  were  placed  in  cold  storage,  and  a  few 
removed  from  time  to  time  and  supplied  with  food.  For 
this  work,  which  was  carried  on  during  the  month  of  April, 
1895,  use  was  made  of  a  double  box  packed  with  sawdust 
and  stored  in  a  refrigerator,  the  temperature  of  which 
averaged  about  40°  F.  The  caterpillars  were  kept  in  corked 
vials  and  removed  as  needed.  At  the  ordinary  tempera- 
ture of  the  refrigerator  the  caterpillars  became  rigid  and 
inactive,  and  remained  so  throughout  the  time  involved  in 
the  experiment.  April  3,  1895,  a  number  of  caterpillars  in 
each  of  the  different  molts,  from  those  just  hatched  to  those 
between  the  fourth  and  fifth  molt  inclusive,  were  placed,  with- 
out food,  in  corked  vials  in  the  refrigerator  box.  All  of 
those  between  the  fourth  and  fifth  molt  died  within  a  day 
or  two,  possibly  due  to  contact  with  the  large  quantity  of 
saliva  which  they  ejected  soon  after  being  placed  in  the  box. 


EFFECTS  OF  TEMPERATURE.  327 

At  intervals  of  a  few  days  several  of  the  caterpillars  of 
the  different  ages  were  removed  from  the  refrigerator  and 
placed  on  suitable  food  in  a  warm  room ;  and  in  this  way  the 
length  of  time  the  caterpillars  could  exist  without  food,  was 
determined.  None  of  the  caterpillars  between  the  third  and 
fourth  molt  were  alive  when  removed  from  the  box  April  6. 
Of  those  between  the  second  and  third  molt,  a  single  cater- 
pillar remained  alive  April  24,  and  this  one,  when  supplied 
with  lettuce  leaves,  revived,  fed  and  molted  at  the  end  of 
nine  days.  April  12,  a  number  of  caterpillars  between  the 
first  and  second  molt  were  removed,  and  when  supplied  with 
food  revived  and  began  feeding.  Several  of  the  newly 
hatched  caterpillars  were  found  to  be  alive  April  24,  and 
when  supplied  with  food  a  number  of  them  were  able  to  feed, 
and  so  reached  maturity,  after  having  been  deprived  of  food 
for  a  period  of  three  weeks. 

A  nearly  full-grown  caterpillar,  confined  in  a  box  July 
30,  1894,  without  food,  lived  until  August  9,  but  died  the 
night  of  that  day.  Lodi  states  that  a  caterpillar  of  this  moth 
in  Europe  went  without  food  for  twenty-seven  days  without 
injury  ("Opuscol.  scelt.,"  vol.  XII,  page  183,  1789). 

Effect  of  Extremes  of  Temperature  on  Caterpillars  of  the 

Gypsy  Moth. 

Effect  of  Heal.  —  Fifty  caterpillars,  in  lots  of  ten,  taken 
from  the  different  molts,  from  those  just  hatched  up  to  and 
including  the  fourth  molt,  were  exposed  for  fifteen  minutes 
to  a  temperature  of  110°  F.,  and  were  then  placed  in  jars 
and  supplied  with  food.  Of  those  just  hatched,  only  one 
died ;  of  those  of  the  first  molt,  three ;  of  the  second  molt, 
three ;  of  the  third  molt,  three ;  and  of  the  fourth  molt, 
three.  The  rest  of  the  caterpillars  survived  and  molted. 
Fifty  caterpillars,  selected  in  the  same  manner  as  those  of 
the  preceding  experiment,  were  exposed  to  a  temperature 
of  120°  for  a  period  of  fifteen  minutes.  Of  those  just 
hatched,  ten  died ;  of  the  first  molt,  ten ;  of  the  second 
molt,  ten ;  of  the  third  molt,  nine ;  and  of  the  fourth  molt, 
only  one.  April  4,  fifty  caterpillars  were  exposed  to  a  tem- 
perature of  130°  for  a  period  of  fifteen  minutes.  The  cater- 
pillars used  in  this  experiment  comprised  those  just  hatched 


328  THE  GYPSY  MOTH. 

and  the   various  molts   up  to   and  including  the   fourth. 
When  taken  from  the  oven,  all  but  one  were  dead. 

Effect  of  Cold.  —  Ten  caterpillars  just  hatched,  also  ten 
from  each  molt  up  to  the  fourth,  were  selected  and  placed  in 
vials,  after  which  they  were  subjected  to  a  temperature  of 
85°  for  a  period  of  five  minutes.  They  were  then  placed  in 
a  cold  box,  where  they  were  exposed  to  a  temperature  of  2° 
above  zero  for  a  period  of  thirty  minutes,  at  the  end  of  which 
time  they  were  removed  to  a  room  where  the  temperature 
was  70°,  and  examined.  Only  one  caterpillar  survived  the 
above  treatment,  but  this  one,  after  a  few  days,  fed  and  grew 
in  a  normal  manner.  Fifty  caterpillars,  in  lots  of  ten,  from 
the  different  molts,  were  transferred  from  a  normal  tempera- 
ture of  70°  and  exposed  to  a  temperature  of  zero  for  a  period 
of  half  an  hour,  when  they  were  returned  to  the  tempera- 
ture from  which  they  were  first  taken.  When  removed,  all 
were  dead.  Fifty  caterpillars  in  the  various  molts,  up  to 
and  including  the  fourth,  were  placed  in  vials  (the  mouths 
of  which  were  stopped  with  cloth  instead  of  cork),  and  then 
removed  from  a  temperature  of  82°  to  a  cold  box,  where 
they  remained  fourteen  hours,  exposed  to  an  approximate 
temperature  of  zero.  All  were  dead  when  taken  out. 

A  study  of  these  experiments  shows  that,  as  a  rule,  the 
small  caterpillars  possess  the  ability  to  resist  a  considerable 
degree  of  cold  but  not  of  heat;  while  the  larger  caterpil- 
lars possess  the  ability  to  resist  the  heat  better  than  the 
cold.  This  is  as  one  would  naturally  expect  to  find  it, 
since  at  the  time  of  hatching  the  weather  is  usually  cool, 
while  the  increase  in  size  of  the  caterpillars  keeps  pace 
with  the  ordinary  increase  of  temperature,  so  that  by  the 
time  the  caterpillars  are  full  grown  we  often  have  a  con- 
siderable degree  of  heat. 

Experiment  in  drowning  Caterpillars. 
In  many  places  the  gypsy  moth  infests  the  trees  along  the 
course  of  streams,  under  such  circumstances  as  to  lead  to 
the  impression  that  they  were  distributed  by  falling  into 
the  water  while  in  the  caterpillar  stage,  and,  drifting  down 
stream  with  the  current,  reached  the  shore,  and,  making 


POSITION  ON  TREES.  329 

their  way  to  suitable  food  plants,  passed  their  transforma- 
tions and  thus  established  new  colonies  down  stream. 

To  determine  the  actual  resistance  of  these  caterpillars  to 
water,  the  following  experiments  were  made  in  July,  1895. 
July  12,  four  jars  were  filled  with  water,  and  at  9  A.M.  five 
gypsy  moth  caterpillars  of  the  fifth  molt  were  placed  in 
each.  In  jar  No.  1,  half  of  the  caterpillars  were  alive  the 
third  day;  the  remainder  died  July  17.  In  jar  No.  2,  one 
caterpillar  died  the  first  and  two  the  second  day ;  the  other 
two  lived  until  the  morning  of  the  fifth  day.  In  jar  No.  3, 
one  died  the  first  and  the  rest  the  fifth  day.  In  jar  No. 
4,  one  died  the  first  and  one  the  second  day,  the  rest  living 
until  the  morning  of  the  fourth  day.  These  results  show  that 
the  gypsy  moth  caterpillars  are  able  to  live  in  water  for  two  or 
three  days,  during  which  time,  if  they  should  fall  into  swiftly 
moving  streams,  they  would  be  carried  a  considerable  dis- 
tance, and  in  this  manner  some  of  the  colonies  found  along 
the  shores  of  streams  may  have  been  established. 

Position  of  Caterpillars  on  Trees. 

To  ascertain  the  normal  position  of  the  caterpillars  of  the 
gypsy  moth  on  trees,  a  tight  board  fence  was  built  around  a 
medium-sized  apple  tree  upon  which  a  number  of  caterpillars 
were  feeding.  The  fence  was  five  feet  in  height,  and  en- 
closed an  area  of  eighteen  by  eighteen  feet.  At  a  height  of 
three  feet  from  the  ground  a  wide  band  of  raupenleim  was 
placed  around  the  fence  on  the  inside,  and  at  the  base  the 
earth  was  banked  up  to  the  height  of  one  foot,  in  order  to 
prevent  the  escape  of  the  caterpillars.  Careful  observations 
were  made  every  morning  by  Mr.  W.  L.  Tower,  on  the 
location  of  the  caterpillars  and  the  places  where  they  had 
gone  to  rest  after  they  stopped  feeding.  As  the  number  of 
caterpillars  on  the  tree  was  not  always  the  same,  no  tabu- 
lated list  of  their  positions  could  be  made ;  yet  the  relative 
number  found  each  day,  in  the  same  place  and  position,  was 
more  constant  than  could  be  expected.  By  adding  the  num- 
ber found  in  each  location  and  the  number  found  on  the  tree 
every  day,  the  percentage  in  each  place  was  found  to  be 
fairly  constant. 


330 


THE  GYPSY  MOTH. 


1894. 

Number 
under  Burlap. 

Number 
on  Trunk. 

Number 
on  Branches. 

Number 
on  Leaves. 

Number 
on  Tree. 

July  16, 

14 

1 

12 

_ 

27 

July  17, 

30 

3 

16 

3 

52 

July  18, 

31 

2 

12 

- 

45 

July  19, 

80 

_* 

47 

7 

134 

July  21, 

75 

* 

38 

_ 

113 

July  23, 
July  25, 

100 
74 

5 

28 
25 

- 

139 
106 

Total,  . 

404 

6    . 

178 

10 

616 

Per   cent. 

(about),  . 

66 

1 

29 

2 

— 

The  average  per  cent,  of  the  number  under  the  burlap  did 
not  vary  much  from  sixty-six.  The  number  found  elsewhere 
on  the  trunk  and  on  the  leaves  of  the  tree  together  did  not 
constitute  three  per  cent,  of  the  whole. 

In  the  early  morning,  before  the  rays  of  the  sun  struck 
the  burlap,  the  caterpillars  were  found  under  it  on  all  sides 
of  the  tree,  but  as  the  sun  rose  higher,  the  greater  part 
of  them  were  on  the  west  and  northern  sides,  away  from 
the  heat  and  light.  As  the  sun  went  from  east  to  west  they 
moved  around  the  tree,  keeping  on  the  shady  side.  This 
was  true  of  the  larger  portion  of  the  caterpillars,  but  in 
some  instances  they  have  been  found  at  mid-day  resting 
under  the  direct  rays  of  the  sun,  with  no  covering  whatever. 
The  caterpillars  that  were  on  the  larger  branches  of  the  tree, 
where  the  sun  did  not  strike  them,  remained  in  the  same 
position  all  day  unless  disturbed,  while  those  on  the  smaller 
branches  moved  around,  keeping  on  the  shady  side  nearly 
all  the  time. 

Spinning  Habits  of  Caterpillars. 

The  amount  of  silk  a  gypsy  moth  caterpillar  is  capable 
of  spinning  has  an  important  bearing  on  the  distribution  ot 
these  insects,  since  it  is  known  that  by  spinning  down  upon 
passing  teams,  etc.,  the  caterpillars  are  carried  from  place  to 
place.  The  more  silk  a  caterpillar  is  capable  of  spinning, 


*  Base  of  tree. 

f  Not  counted  in  the  results,  as  they  were  pupating. 


SPINNING  HABITS.  331 

the  greater  are  its  chances  of  being  carried  into  new  localities. 
To  learn  the  quantity  of  silk  that  one  of  these  caterpillars 
can  spin,  a  reel  was  made  and  mounted  in  a  frame.  Cater- 
pillars were  taken  on  a  soft  brush  and  then  jarred  off  into 
space.  This  caused  them  to  spin,  when,  by  attaching  the 
end  of  the  thread  to  the  wheel  and  manipulating  the  cater- 
pillars carefully,  the  silk  was  reeled  off  and  a  record  kept  of 
the  number  of  revolutions  of  the  wheel,  until  the  caterpillars 
could  not  or  would  not  spin.  It  was  found  that  they  spun 
best  when  a  slight  current  of  air  was  blown  upon  them.  In 
this  manner  caterpillars  of  known  ages  were  experimented 
with.  Many  of  these  experiments  gave  only  negative  results, 
for  the  manipulation  necessary  in  getting  the  thread  started 
often  disturbed  them  so  that  they  would  spin  only  a  few  feet. 
The  following  results  were  obtained  from  a  number  of  the 
experiments :  — 

March  22  :  Four  caterpillars,  just  hatched,  were  taken  be- 
fore any  of  their  store  of  silk  had  been  drawn  upon.  The 
first  spun  4  feet  and  6  inches,  the  second  spun  9  feet  and  1 
inch,  the  third  spun  38  feet  and  2  inches,  and  the  fourth  spun 
69  feet  and  4  inches, — a  distance  greater  than  the  height  of 
an  average  shade  tree.  March  14 :  Of  five  first-molt  cater- 
pillars, the  first  spun  53  feet  and  2  inches,  the  second  24 
feet  and  2  inches,  the  third  3  feet  and  2  inches,  the  fourth  6 
feet  and  4  inches  and  the  fifth  7  feet. 

April  23  :  Three  more  caterpillars,  of  the  first  molt,  were 
experimented  with,  and  the  following  results  obtained :  the 
first  spun  25  feet  and  3  inches,  the  second  22  feet  and  6 
inches  and  the  third  47  feet  and  9  inches.  March  22  :  Of 
two  second-molt  caterpillars,  the  first  spun  8  feet  and  the 
second  2  feet.  Other  caterpillars,  in  the  later  molts,  were 
tried,  but  they  could  not  be  induced  to  spin.  There  seems 
to  be  a  decrease  in  spinning  power  as  the  caterpillar  grows 
older.  Caterpillars  of  the  second,  third  and  fourth  molt  have 
been  seen  spinning  down  to  a  considerable  distance  from  trees 
on  which  they  were  feeding,  and  in  this  manner  they  were 
able  to  make  the  wind  and  passing  teams  aid  them  in  finding 
their  way  to  suitable  food  plants. 

The  last  thing  before  entering  upon  the  rest  previous  to 
molting  is  the  spinning  of  a  number  of  threads,  forming  a 


332  THE  GYPSY  MOTH. 

small  silk  mat,  a  little  longer  in  diameter  than  the  length  of 
the  body  of  the  caterpillar.  When  rocks  have  been  burned 
over,  caterpillars  have  been  seen  spinning  down  to  escape  the 
smoke  and  heat.  They  frequently  spin  threads  from  fences 
to  the  neighboring  trees.  The  insect  also  spins  a  scanty 
cocoon  for  a  shelter  and  support  during  the  pupal  stage. 

The  Process  of  Pupation. 

Cocoon.  —  When  the  caterpillar  is  fully  grown,  it  seeks 
some  sheltered  spot  (Plates  47,  49),  and  rests  quietly  for 
about  twenty-four  hours.  It  then  empties  its  alimentary 
canal,  the  discharge  being  of  a  semi-fluid  nature,  and  con- 
taining an  abundance  of  chlorophyl,  showing  it  to  be,  in 
part  at  least,  the  remains  of  food.  In  about  one  hour  after 
this  discharge,  the  caterpillar  begins  to  spin  a  frail  cocoon, 
which  is  composed  of  a  few  coarse  brown  silken  threads, 
occasionally  enclosing  a  leaf  or  other  material.  In  spinning, 
it  first  places  its  spinneret  close  to  the  surface  on  which  the 
cocoon  is  to  be  formed,  and  presses  out  a  drop  of  the  silk- 
forming  fluid,  which  serves  as  an  anchor  for  the  silk  thread 
which  is  then  spun  out.  It  first  spins  a  few  long  threads, 
which  usually  exceed  the  length  of  the  cocoon  when  finished. 
After  a  number  of  these  long  threads,  which  connect  various 
points  and  serve  as  a  sort  of  frame,  have  been  formed,  the 
caterpillar  begins  to  spin  more  rapidly,  and  to  place  short 
threads  between  the  long  ones,  working  always  from  the 
inside,  and  changing  at  intervals  from  one  side  of  the  cocoon 
to  the  other.  Where  the  threads  cross  each  other  they  are 
fastened  together  by  a  drop  of  the  fluid  in  much  the  same 
manner  as  at  the  starting  of  the  cocoon.  In  spinning,  the 
labial  palpi  and  the  feet  are  used  to  grasp  the  threads.  As 
a  rule,  the  spinning  is  not  completed  at  a  single  operation, 
since  the  caterpillar  rests  several  tunes,  the  rests  ranging 
from  a  few  minutes  to  five  or  six  hours.  The  actual  time 
spent  in  spinning  is  about  six  hours.  After  completing  its 
network  of  silk  the  caterpillar  rests  quietly,  except  for  occa- 
sional spasmodic  twitchings  of  the  body,  hanging  head  down- 
ward, and  pupates  at  the  end  of  about  three  hours. 

Pupation.  —  When  the  process  of  pupation  begins,  the 
skin  commences  to  contract  and  wrinkle  on  the   posterior 


PLATE  47.     Mass  of  pupee  between  the  trunks  of  two  trees.    Fr 
photograph  taken  at  the  Winning  colony,  Woburn,  July,  1895. 


PLATE  48. 


EXPLANATION  OF  PLATE  48. 

[AH  figure,  enlarged.] 


Drawn  by  R.  A.  COOLEY. 


1.  Ventral  view  of  male  pupa. 

2.  Ventral  view  of  female  pupa. 

3.  Dorsal  view  of  female  pupa. 

4.  Lateral  view  of  female  pupa. 

5.  Genital  markings  of  male  pupa. 

6.  Genital  markings  of  female  pupa. 

7.  Chitinized  hook  from  cremaster  of  pupa, 

greatly  enlarged. 

8.  Aerostatic  hair  from  newly  hatched  cater- 

pillar, greatly  enlarged. 

9.  Normal  hair  from  caterpillar,  greatly  enlarged. 


THE   PUPA.  333 

segments  of  the  caterpillar,  showing  that  the  pupa  is  being 
withdrawn  from  that  part.  The  pupa  is  pushed  forward 
by  a  vigorous  use  of  the  cremaster.  In  this  manner  the 
skin  on  the  posterior  segments  is  pushed  back,  and  the 
pressure  on  the  anterior  segments  becomes  so  great  as  to 
nearly  bend  under  that  part  of  the  body.  The  insect  takes 
short  rests  at  intervals  during  this  process.  Next,  the  skin 
on  the  fourth  segment  splits  along  the  dorsal  line,  the  split 
continuing  forward  and  backward,  and  in  a  few  seconds 
extends  from  the  base  of  the  head  to  the  annulation  between 
the  fourth  and  fifth  segments,  the  pupa,  in  the  mean  time, 
forcing  itself  outward  against  the  opening  thus  made.  In  a 
few  seconds  more  the  movements  of  the  pupa,  aided  by  the 
pressure  from  behind,  which  it  is  able  to  exert  by  means 
of  its  cremaster,  splits  the  head  down  on  each  side  of  the 
clypeus  to  the  mouth  parts,  and  the  pupa  emerges  by  pass- 
ing outward  through  the  opening,  the  whole  process  taking 
about  fifteen  minutes. 

The  newly  formed  pupa  is  very  soft  and  of  a  light  color, 
with  the  remains  of  the  larval  tubercles  and  markings 
plainly  visible,  but  these  disappear  and  the  pupa  grows 
harder  and  darker  when  exposed  to  the  air.  Caterpillars, 
in  their  attempts  to  pupate,  sometimes  burst  the  thin  pupal 
skin  and  die  from  the  escape  of  the  fluids  from  the  body. 
In  changing  from  the  larval  to  the  pupal  stage,  the  insect 
loses  about  thirty-five  per  cent,  in  size  and  nearly  forty-five 
per  cent,  in  weight.  A  small  part  of  the  weight  is  left  in 
the  larval  skin  and  silk.  How  the  insect,  as  a  rule,  fastens 
itself  to  the  silk  in  which  it  is  enclosed,  is  not  fully  known. 
In  one  case,  however,  a  pupa  was  seen  to  emerge  and  fall 
into  the  network  of  silk,  when,  by  a  wriggling  motion,  it 
picked  up  the  silk  threads  on  its  cremaster  and  then  hung, 
from  gravity,  head  downward. 

The  maximum  time  spent  in  the  pupal  stage  by  one 
hundred  females  was  found  to  be  14  days,  the  minimum  7 
and  the  average  10.65.  The  maximum  time  spent  in  the 
pupal  stage  by  eighty-eight  males  was  found  to  be  17  days, 
the  minimum  9  and  the  average  13.41  days. 

Pupa  (Plate  I,  Fig.  5,  and  Plate  48).— The  pupse  of  the 
males  vary  in  length  from  three-fifths  to  four-fifths  of  an  inch, 


334  THE  GYPSY  MOTH. 

including  the  cremaster,  or  blunt  spine  at  the  end  of  the 
abdomen,  while  thp^e  of  the  females  vary  from  three-fifths  to 
one  and  two-fifths  inches.  Fig.  5,  Plate  I,  was  taken  from 
one  of  extraordinary  size.  The  following  description  was 
made  from  the  study  of  thirty-nine  males  and  one  hundred 
and  twenty-one  females  :  — 

They  vary  in  color  from  chocolate  to  dark  reddish-brown, 
and  are  cylindrical  or  fusiform,  rounded  anteriorly  and  taper- 
ing posteriorly  to  the  cremaster,  which  is  armed  at  the  tip 
with  a  cluster  of  minute  hooks,  one  of  which  is  shown  at 
Fig.  7,  greatly  enlarged.  The  covers  to  the  various  parts 
of  the  body,  as  the  wings,  legs,  antennae,  etc.,  are  plainly 
marked ;  those  of  the  wings  are  quite  broad,  and  reach  to 
the  posterior  third  of  the  fifth  segment,  while  those  of  the 
antennae  are  strongly  curved,  being  much  wider  in  the 
males  than  in  the  females.  At  the  front  edge  of  the  meso- 
thorax,  on  each  side,  is  an  oval,  dark  reddish-brown  velvety 
spot,  very  distinct  in  some  examples  but  nearly  invisible  in 
others.  Ochre-yellow  hairs,  arranged  in  groups,  occur  on 
the  eye,  head  and  palpi  covers,  across  the  collar  and  thorax, 
and  in  eight  equidistant  rows  along  the  abdominal  segments. 
Some  of  the  hairs  in  the  groups  across  the  collar  and  thorax 
are  dark  brown.  The  abdominal  segments  are  more  or  less 
punctured,  and  the  hairs  arise  in  small  circles.  At  the  base 
of  the  cremaster,  on  the  ventral  side,  is  an  elliptical  depres- 
sion, with  curved  ridges  on  each  side.  In  the  males,  on  the 
middle  of  this  segment,  in  front  of  the  depression,  is  a  small 
raised  tubercle,  with  a  longitudinal  slit  on  the  top  of  it 
(Fig.  5),  while  in  the  females  this  tubercle  is  wanting;  on 
the  extreme  front  edge  of  this  same  segment,  however,  there 
is  a  fine  longitudinal  slit,  but  the  surface  at  this  place  is  not 
raised  (Fig.  6). 

Attached  Pupae. — In  order  to  determine  the  best  plan  for 
raising  the  finest  specimens  of  gypsy  moths,  a  number  of 
experiments  were  made  in  the  laboratory.  In  six  of  the  ex- 
periments the  pupse  were  fastened  to  the  bottom  of  a  small 
pasteboard  box,  in  which  they  were  confined  by  means  of  a 
pin  put  through  the  little  bunch  of  silk  at  the  end  of  the  cre- 
master, and  then  into  the  bottom  of  the  box.  The  moths  all 
emerged  from  these  pupse,  and  were  in  good  condition.  In 


PUPATION.  335 

two  experiments  a  very  fine  pin  was  run  through  the  cre- 
master,  as  near  to  the  end  as  possible  ;  but  it  was  found  that 
the  pin  injured  the  pupae,  and  consequently  they  died  without 
emerging.  A  very  fine  pin  was  run  through  the  last  seg- 
ment of  a  pupa,  which  began  to  emerge,  but  died,  being 
unable  to  complete  the  process.  In  several  other  cases  pupse 
were  stuck  to  the  bottom  of  the  box  by  means  of  a  drop  of 
mucilage  or  a  drop  of  sticky  fly-paper  gum.  This  was  un- 
satisfactory, however,  for  the  pupse,  in  wriggling  about,  got 
themselves  covered  with  the  gum,  and  the  few  which  did 
emerge  were  in  very  poor  condition. 

Mass  of  Pupw. —  When  about  to  pupate,  the  caterpillars, 
when  numerous,  collect  in  masses  to  spin  their  cocoons.  On 
the  flat  side  of  a  rock  one  of  these  masses  (Plate  49)  was 
found  which  measured  eighteen  inches  in  length  and  eight 
inches  in  width,  the  whole  being  covered  by  one  large  net- 
work of  silk.  Beneath  two  partly  eaten  leaves  of  oak  forty- 
nine  caterpillars  had  pupated,  and  another  mass  was  found 
in  a  groove  between  the  trunks  of  two  small  trees  (Plate 
47),  containing  at  least  three  hundred  pupae  and  pupa-cases. 

Pupation   in   the  Field. 

To  learn  the  proportion  of  caterpillars  which  pupate  on 
trees  and  on  the  ground,  as  well  as  the  per  cent,  of  those 
parasitized,  a  study  was  made  of  the  "  Winning  "  colony  at 
Woburn,  in  the  latter  part  of  July,  1895,  the  results  of 
which  show  that  the  larger  part  of  the  caterpillars  pupated 
in  the  trees.  On  the  border  of  the  colony,  about  forty  per 
cent,  pupated  above  the  burlap ;  while  in  the  centre,  about 
sixty  per  cent,  were  found  to  have  pupated  above  it.  These 
facts  confirm  the  generally  accepted  opinion  that,  when  very 
abundant,  the  per  cent,  of  caterpillars  pupating  upon  the 
trees  is  somewhat  increased. 

Of  the  caterpillars  which  pupated  elsewhere  in  the  col- 
ony, the  proportion  was  equally  divided  between  those  that 
pupated  on  the  ground  and  those  which  passed  the  pupal 
stage  on  the  trunks  and  under  the  burlaps  on  the  trees. 
All  pupce  which  gave  evidence  of  parasites,  as  well  as  the 
empty  pupa-cases  from  which  parasites  had  apparently 
emerged,  were  counted  as  parasitized.  The  per  cent,  of  the 


336  THE   GYPSY  MOTH. 

sexes  found  to  be  parasitized  was  9.7  per  cent,  of  the  males 
and  7.5  per  cent,  of  the  females.  This  does  not  agree  with 
observations  previously  made,  where  the  larger  per  cent, 
parasitized  were  found  to  be  females.  The  greater  part  of 
the  parasitized  pupae  were  brought  in,  and  many  were  found 
to  contain  Dipterous  larvae.  In  most  cases  no  parasite  ima- 
goes were  obtained  from  these  pupae,  although  some  of  the 
Dipterous  maggots  have  not  yet  transformed, 

THE  IMAGO. 

The   Process   of  Emerging. 

The  emerging  of  the  imago  from  the  pupa  is  accom- 
plished as  follows :  when  the  insect  is  fully  developed  and 
ready  to  come  forth,  it  forces  off  the  cap  on  the  anterior 
ventral  part  of  the  pupa,  comprising  the  antennae,  head  and 
leg  shields,  and  through  the  opening  thus  formed  the  antennae 
appear,  and  then  the  first  two  pairs  of  legs  are  drawn  out. 
The  cap  is  attached  to  the  rest  of  the  pupa  at  its  apex,  and 
its  larger  anterior  end  is  pushed  away  from  the  body  by 
means  of  the  feet.  The  legs  at  first  are  stiff  at  the  joints 
between  the  tibiae  and  tarsi.  Next,  the  juncture  of  the  wing 
covers  on  the  top  of  the  back  splits,  then  the  posterior 
margin  of  the  wing  covers  comes  off,  and  the  insect  crawls 
up  and  out  of  the  pupa-case,  the  hind  legs  coming  out  at  the 
same  time  as  the  wings.  This  process  requires  from  five 
minutes  to  five  hours,  according  to  the  resistance  of  the  pupa- 
case  and  the  vigor  of  the  enclosed  imago.  When  the  moth 
first  emerges  it  is  quite  moist,  but  soon  dries  off.  From 
twenty  minutes  to  two  hours  are  required  for  the  develop- 
ment of  the  wings. 

Description  of  the  Imago. 

The  following  description  was  made  from  thirty  males  and 
thirty-seven  females.  The  males  (Plate  I,  Fig.  3)  measure 
from  37  to  50  mm.  (one  and  one-half  to  two  inches)  be- 
tween the  tips  of  the  expanded  wings.  The  ground  color 
of  all  the  wings  is  brownish  yellow,  varying  in  intensity  in 
different  examples,  but  somewhat  lighter  beneath.  The 
head,  thorax,  antennae  and  upper  side  of  the  palpi  are 


THE  IMAGO.  337 

grayish  brown,  inclining  to  mouse  color  in  some  specimens. 
The  under  side  of  the  entire  body,  legs  and  palpi  is  some- 
what lighter  than  the  under  side  of  the  wings. 

The  markings  on  the  fore  wings  are  dark  brown,  and  are 
as  follows  :  the  half  line  starts  from  the  costa,  near  the  base 
of  the  wing,  and  extends  half  way  across  the  wing.  The 
transverse  anterior  line  arises  from  the  basal  fourth  of  the 
costa  and  crosses  the  wing  as  a  scalloped  line.  Just  outside 
of  this  line,  on  the  cell,  is  the  small  orbicular  spot.  The 
reniform  spot  is  crescent  shaped,  and,  resting  on  the  outer 
end  of  the  cell,  extends  across  its  entire  width.  The  median 
shade  is  quite  obscure,  but  is  bent  out  around  the  end  of  the 
cell,  and  toothed  along  the  outside.  The  transverse  poste- 
rior line  arises  from  the  outer  fourth  of  the  costa,  is  some- 
what curved  and  toothed  on  the  veins,  and  terminates  just 
within  the  anal  angle.  The  subterminal  line,  a  little  outside, 
is  similar  to  the  transverse  posterior  line  and  parallel  with 
it.  The  terminal  space  is  usually  somewhat  darker  than  the 
rest  of  the  wing,  and  all  the  cross  lines  are  heavier  on  the 
costa  than  elsewhere.  The  fringe  is  cut  with  dark  brown 
between  the  veins. 

The  hind  wings  have  a  faint  discal  lunule  at  the  end  of  the 
cell,  and  the  terminal  shade  is  darker  brown  than  the  rest  of 
the  wing.  The  upper  side  of  the  abdomen  is  of  the  same 
color  as  the  upper  side  of  the  hind  wings,  and  has  a  row  of 
brownish  spots  along  the  middle. 

The  outside  of  the  third  and  fourth  joints  of  the  tarsi  and 
the  ends  of  the  femora  on  the  upper  side  are  brown ;  the  fore 
and  middle  tibiae  are  pale  mouse  colored  on  the  outside. 

The  females  (Plate  I,  Fig.  1)  measure  from  37  to  62  mm. 
(one  and  one-half  to  two  and  one-half  inches)  between  the 
tips  of  the  expanded  wings.  The  entire  body  and  wings 
above  and  beneath  are  yellowish  white,  except  the  abdomen 
beneath  and  towards  the  end  above,  which  is  pale  yellow. 
The  markings  of  the  fore  wings  are  dark  brown  or  nearly 
black,  but  vary  much  in  intensity  in  different  specimens, 
being  almost  entirely  obliterated  in  some  examples.  The 
half  line  at  the  base  of  the  wing,  the  orbicular  and  reniform 
spots,  the  costal  end  of  the  transverse  lines  and  the  black 
spots  in  the  cilia  are  quite  pronounced.  The  form  and 


338 


THE  GYPSY  MOTH. 


position  of  the  lines  and  spots  are  the  same  as  in  the  males. 
The  fore  wings  are  longer,  narrower  and  more  pointed  than 
in  the  males.  The  hind  wings  have  a  faint  discal  spot  and 
a  subterminal  line  which  is  toothed  along  the  outside  on  the 
veins,  and  the  cilia  have  black  basal  spots  between  the  veins. 
The  antennae  and  legs  are  dark  brown,  but  the  hair  on  the 
femora  and  tibiae  is  yellowish  white. 

The  imago  is  subject  to  considerable  variation  in  size. 
The  following  table  gives  the  dimensions  of  the  largest  and 
the  smallest  imagoes  of  each  sex,  taken  in  the  field  :  — 


Expanse 
of  Fore 
Wings. 

Expanse 
of  Hind 
Wings. 

Length 
of 
Body. 

Diameter 
of 
Thorax. 

Diameter 
of 
Abdomen. 

mm. 

mm. 

mm. 

mm. 

Largest  male, 

46 

37 

18 

5 

3 

Smallest  male, 

33 

25 

12 

4 

2 

Largest  female, 

71 

53 

31 

8 

12 

Smallest  female,     . 

44 

34 

16 

5 

6 

Mr.  J.  H.  Leech,  in  the  "Proceedings  of  the  Zoologi- 
cal Society  of  London,"  Vol.  LVI,  page  630,  expresses  the 
opinion  that  the  Japanese  gypsy  moths,  which  have  been 
described  as  distinct  species,  do  not  differ  from  those  of 
Europe,  except  in  size,  and  he  regards  them  only  as  forms, 
and  not  distinct  species.  He  gives  the  extremes  of  size  of 
males  and  females  in  Japan  and  Corea  as  follows:  "Ex- 
panse of  wings  of  largest  male,  71  mm. ;  smallest  male, 
37  mm.;  largest  female,  114  mm.;  smallest  female,  48 
mm."  Mr.  Leech  also  gives  the  size  of  European  examples 
of  the  gypsy  moth  as  follows:  "Largest  male,  54  mm.; 
smallest  male,  32  mm. ;  largest  female,  93  mm. ;  smallest 
female,  42  mm."  I  have  in  my  collection  three  males  from 
Pekin,  China,  which  measure  46,  50  and  54  mm.,  respec- 
tively, in  expanse  of  wings;  and  several  male  examples 
from  Europe,  the  largest  of  which  measures  43  mm.  and 
the  smallest  37  mm.  I  can  see  no  difference  between  the 
examples  from  China  and  those  from  Europe,  except  in 
size. 


PLATE  50. 


EXPLANATION  OF  PLATE  50. 

[All  figure*  greatly  enlarged.] 


Drawn  by  C.  P.  LOUNSBURY. 


1.  Dorsal  view  of  male  moth. 

2.  Lateral  view  of  genitalia. 

3.  Ventral  view  of  genitalia. 

4.  Antenna  of  the  male. 

5.  Single  filament  from  antenna. 

6.  Section  of   antennal   filament,  showing   insertion 

of  the  finer  lateral  filaments. 


HERMAPHRODITES.  339 


Hermaphrodites. 

Three  specimens  of  the  gypsy  moth  were  taken  in  Med- 
ford,  Mass.,  which  are  what  Ochsenheimer  would  call  perfect 
hermaphrodites.  One  has  the  right  half  of  the  body,  with 
the  wings  and  antenna  of  that  side,  of  the  form,  color  and 
markings  of  the  female ;  while  the  left  side  of  the  body,  with 
its  wings  and  antenna,  is  male.  The  second  specimen  is 
male  on  the  right  side,  and  female  on  the  left.  In  both  of 
these  examples  the  frenulum  is  single  on  the  male  side,  but 
divided  on  the  female.  In  the  third  specimen,  the  antenna 
and  both  wings,  on  the  left  side,  are  female,  while  on  the 
right  side,  the  antenna  and  both  wings  are  male.  The 
abdomen  is  female  in  size  and  form,  but  the  right  side  is 
darker  than  the  left,  looking  more  like  the  male  in  color. 

As  the  sexes  of  this  moth  diner  so  much  in  the  form  and 
color  of  the  wings  and  in  the  pectinations  of  the  antennae, 
an  hermaphrodite  is  a  remarkable  insect  in  appearance,  and 
seems  almost  to  suggest  that  it  is  a  work  of  art.  Hermaph- 
roditism  in  this  species  is  occasionally  met  with  in  Europe, 
several  cases  being  on  record  in  the  European  journals. 

External  Anatomy  of  the  Moth. 

The  head  is  rather  small,  and  joined  by  a  very  short  neck 
to  the  comparatively  large  thorax.  This  is  followed  by  the 
abdomen,  which,  in  the  male  (Plate  50,  Fig.  1),  is  medium 
in  size,  gradually  tapering  to  the  last  two  segments.  These 
taper  more  rapidly  to  the  genitalia  or  external  genital  or- 
gans, which  consist  of  a  genital  hook  and  pair  of  clasps 
(Plate  50,  Figs.  2  and  3).  The  abdomen  of  the  female  is 
enormously  distended.  The  front  is  smooth  and  very  slightly 
rounded ;  the  maxillae  or  sucking  tube  is  rudimentary ;  the 
palpi  small,  extended  forward  horizontally  (Plate  51,  Fig. 
la),  the  basal  and  terminal  joints  being  about  equal  in 
length,  while  the  middle  joint  is  about  three  times  as  long 
as  either  of  the  others,  and  covered  with  fine  hairs  loosely 
arranged  over  the  surface,  similar  to  those  that  cover  the 
surface  of  the  head.  There  are  no  ocelli  present.  The 
antennae  are  bipectinated  very  strongly  in  the  male  (Plate 
50,  Fig.  4),  while  in  the  female  the  pectinations  are  very 


340  THE  GYPSY  MOTH. 

much  shorter  and  stouter  (Plate  51,  Fig.  3).  The  pectina- 
tions of  the  male  antennae  (Plate  50,  Fig.  5)  are  somewhat 
curved,  and  taper  slightly  toward  the  outer  end,  where  they 
terminate  in  a  tooth  on  one  side  and  a  much  longer  spine 
on  the  other;  there  are  numerous  hairs,  about  twice  as 
long  as  the  diameter  of  the  pectinations,  scattered  over  the 
surface.  Plate  50,  Fig.  6,  shows  a  portion  of  a  pectination, 
with  the  bases  of  four  of  these  hairs,  and  still  finer  hairs, 
scattered  over  the  surface,  which  is  thrown  into  very  minute, 
irregular  longitudinal  ridges,  visible  only  under  a  high  power 
ol  the  microscope.  The  female  antennae  (Plate  51,  Fig.  3) 
have  minute,  elongated,  tooth-like  scales  and  bristle-like 
hairs  over  the  surface  (Plate  51,  Fig.  4),  and  the  pecti- 
nations are  cylindrical,  stout  and  terminate  obliquely  in  a 
point  at  the  outer  end,  near  which,  on  the  lower  side,  is  a 
short  bristle.  There  are  minute  hairs  sparsely  scattered  over 
the  surface,  as  shown  in  Plate  51,  Fig.  4  6,  and  scattered  be- 
tween these  are  minute  pits,  around  the  edge  of  which  is  a 
row  of  minute  hairs  (Plate  51,  Fig.  4  «). 

The  legs  (Plate  51,  Figs.  5,  6  and  7)  are  moderately 
long  and  of  medium  size,  with  the  first  or  coxal  segment 
somewhat  conical  in  form ;  the  second  segment  (trochan- 
ter)  much  smaller,  its  length  being  about  equal  to  the 
thickness;  the  third  and  fourth  segments  (femur  and  tibia) 
are  of  nearly  equal  length.  The  outer  part  of  the  leg  (tar- 
sus) consists  of  five  segments,  the  first  of  which  is  about  the 
length  of  the  three  following,  and  the  last  has  a  pair  of  di- 
verging claws  at  the  end,  with  a  fleshy  organ  (pulvillus)  be- 
tween them  (Plate  51,  Figs.  9  and  10).  The  claws  have  a 
somewhat  flattened  under  surface,  with  a  row  of  small  blunt 
teeth  along  each  side.  The  fore  legs  (Plate  51,  Fig.  5)  have 
a  long  sinuous  spur  (tibial  epiphysis)  attached  to  the  tibia 
near  the  base  and  extending  a  little  beyond  the  end.  The 
whole  side  of  this  epiphysis  next  to  the  tibia  is  covered  with 
fine  bristles,  forming  a  brush-like  organ.  The  tibiae  of  the 
middle  legs  have  a  pair  of  unequal  spurs  at  the  end,  and  the 
hind  tibiae  have  a  similar  pair  at  the  end  and  a  pair  about  one- 
fourth  of  the  length  of  the  tibia  above.  All  these  spurs  have 
the  outer  part  obliquely  flattened,  with  a  row  of  short,  blunt 


EXPLANATION  OF  PLATE  51. 

[All  fitrnrea  greatly  enlarged*] 


Drawn  by  C.  P.  LOUNSBURY. 


1.  Lateral  view  of  the  anterior  part  of  body 

of  female. 

2.  Ventral  view  of  female  genitalia. 

3.  Antenna  of  the  female. 

4.  Section  of  antenna,  showing  sensory  pits. 

5.  Fore  leg. 

6.  Middle  leg. 

7.  Hind  leg. 

8.  Part  of  hind  leg,  with  abnormal  appendage. 

9.  Foot,  seen  from  below. 
10.  Foot,  seen  from  the  side. 


PLATE  51. 


EXTERNAL   ANATOMY.  341 

teeth  around  the  edge  of  the  flattened  surface  (Plate  51, 
Figs.  6  and  7).  On  one  of  the  hind  legs  of  the  male,  at  the 
end  of  the  tibia,  was  found  an  additional  appendage  on  the 
side  opposite  to  the  spurs  (Plate  51,  Fig.  8).  This  is  the 
only  monstrosity  we  have  thus  far  seen  in  the  gypsy  moth. 

The  wings  differ  somewhat  in  form  in  the  two  sexes,  the 
fore  wings  of  the  female  being  longer  and  more  pointed 
than  those  of  the  male.  The  venation  is  shown  in  Plate  52, 
Figs.  1  and  2  (male),  3  and  4  (female).  The  frenulum  at 
the  base  of  the  hind  wing  of  the  male  consists  of  a  single 
pointed  bristle,  while  in  the  female  it  is  composed  of  a  clus- 
ter of  much  finer  pointed  bristles  (Fig.  4).  The  surface  of 
the  wings  is  sparsely  covered  with  scales  and  hairs  (Fig.  7), 
and  around  the  outer  border  of  both  the  fore  and  hind  wings, 
at  quite  equal  distances  apart,  is  a  row  of  blunt  spines,  two 
of  which  are  shown  in  Fig.  8,  and  one  still  more  enlarged 
is  represented  in  Fig.  9.  These  spines  appear  to  be  hol- 
low, with  a  fine  aperture  at  the  outer  end.  Near  the  hinder 
margin,  towards  the  base  of  the  fore  wing,  is  an  oval  area 
(Plate  52,  Fig.  5),  the  surface  of  which  is  covered  with 
minute  stout  spines  (Fig.  6).  The  lateral  surface  of  the 
metascutum  (Plate  51,  Fig.  1  ^)  is  covered  with  a  similar 
series  of  spines. 

In  the  "Berliner  Entomologische  Zeitschrift,"  Yol. 
XXXI,  1887,  Dr.  W.  Donitz  describes  a  singing  Lepi- 
dopteron.  After  referring  to  the  list  of  Lepidoptera  which 
produce  sounds,  given  by  Swinton  in  his  work  on  "Insect 
Variety,"  he  describes  an  apparatus  which  he  discovered  in 
Dionychopus  niveus  Men.,  a  Bombycid  moth  found  in  Japan, 
and  also  in  Siberia.  He  states  that  when  a  fresh  male  is  held 
in  such  a  manner  that  the  wings  can  be  moved  back  and  forth 
on  each  other,  one  can  hear  a  slight  chirping  sound,  which 
continues  as  long  as  the  wings  are  moved.  He  figured  and 
described  an  apparatus,  on  the  basal  part  of  the  fore  wings, 
similar  to  that  described  above  ;  and  a  corresponding  area  on 
the  hind  wings,  where  that  of  the  fore  wings  overlies  this 
organ  on  the  hind  wings.  In  the  gypsy  moth  no  such  organ 
exists  on  the  hind  wing,  but  its  counterpart  is  found  on  the 
side  of  the  metathorax,  as  stated  above,  where  the  organ  in 


312  THE   GYPSY  MOTH. 

the  fore  wings,  when  closed,  rests  on  the  side  of  the  thorax. 
A  similar  organ  occurs  in  Ocneria  rubea  of  Europe,  of  the 
same  structure  and  in  the  same  place  as  in  the  gypsy  moth. 

The  scales  on  the  wings  vary  in  form,  as  shown  in  Plate 
52,  Figs.  10—20.  The  striations  are  not  shown  in  all  these 
figures.  Fig.  15  represents  one  of  the  short  and  broad 
scales  with  the  longitudinal  strias.  Figs.  21  and  22  repre- 
sent cross-sections  of  a  scale,  the  first  from  near  the  base, 
the  second  from  the  broader  part  of  the  scale.  After  suitable 
preparation  and  embedding  inparaffine,  a  portion  of  the  wing 
was  sectioned  and  these  figures  drawn  from  the  mounted 
sections.  The  surface  of  the  scale  next  the  membrane  of 
the  wing  is  smooth,  while  the  outer  surface  is  covered  with 
longitudinal  ridges. 

The  abdomen  of  the  female  (Plate  51,  Fig.  1)  is  very 
large,  and  densely  clothed  with  yellowish  hairs,  especially 
on  the  under  side  towards  the  posterior  part.  One  of  these 
hairs  is  represented  in  Plate  52,  Fig.  19,  and  a  section  of 
it,  near  the  basal  fourth  of  the  hair,  greatly  enlarged  at 
Fig.  10.  The  surface  is  covered  with  minute  spines,  which 
incline  towards  the  apex,  and  it  also  appears  to  be  marked 
with  irregular  cross-wrinkles.  The  ovipositor  of  the  female 
is  shown  in  Plate  51,  Fig.  2. 

MATING. 

After  emerging  the  female  crawls  a  short  distance  from 
the  pupa-case,  and,  by  the  time  the  wings  have  expanded, 
and  sometimes  before,  she  begins  to  attract  or  "assemble" 
the  imagoes  of  the  opposite  sex.  In  colonies  where  the 
males  are  abundant,  they  often  attempt  to  mate  with  females 
almost  as  soon  as  the  latter  emerge.  Seeking  the  female,  the 
male  flies  in  a  zigzag  course  until  she  is  found,  when  he 
hovers  around  her  for  a  few  minutes,  rapidly  vibrating  his 
wings. 

The  time  spent  in  mating  has  been  found  to  vary  from 
twenty-five  minutes  to  three  hours  and  eighteen  minutes ; 
the  average  time  of  twenty-four  pairs  being  one  hour  and 
nine  minutes.  Alter  mating,  the  male  is  quite  stupid,  but 
in  about  half  an  hour  regains  his  normal  activity. 


EXPLANATION  OF  PLATE  52. 

i  All  figure*  enlarged.] 


Drawn  by  R.  A.  COOLEY. 


1.  Venation  of  fore  wing  of  male. 

2.  "          "    hind    "      "      " 

3.  "          "    fore  wing  of  female. 

4.  "          "    hind    "      "        " 

5.  Base  of  fore  wing,  showing  outline  of  the  spiny  area. 

6.  Portion   of  the    spiny  area,  showing    the    spines,  greatly  en- 

larged. 

7.  Area  from  near   the    middle    of  the    upper  side  of  the    fore 

wing  of  female,  showing  scales  and  hairs. 

8.  External  outer  border  of  wing,  showing  spines  and  a   fringe 

scale. 

9.  Single  blunt  spine  from  outer  border. 

10.  Section  of  figure  19  greatly  enlarged,  showing  spiny  sur- 
face. 

n,      12,   13,   14,   16.     Various  types  of  scales  from  the  wings. 

15.  Scale  from  the  upper  side  of  the  fore  wing  of  the  female, 
showing  the  striae. 

17,      1 8.     Scales  from  the  fringe  of  the  fore  wing. 

19.  Hair  from  the  end  of  the  abdomen  of  the  female. 

20.  "        "       "      "         "  "  "'       male. 

21.  Section  of  a  scale  near  the  base. 

22.  "         "        "        "       "     middle. 


PLATE  52. 


POLYGAMY.  343 


Fertilization   Experiment. 

To  determine  the  length  of  time  necessary  for  fertilization, 
twenty-five  virgin  females  were  exposed  in  infested  localities. 
After  mating  had  commenced,  the  males  were  removed  at 
the  end  of  given  periods  of  time,  varying  from  one  minute 
to  one  hour ;  the  females  were  placed  in  boxes,  and  allowed 
to  deposit  their  eggs. 

In  all  cases  where  the  male  was  removed  before  six 
minutes,  the  eggs  proved  infertile ;  but  where  they  were 
allowed  to  remain  beyond  that  time,  the  eggs  were  fertile. 

Polygamy. 

As  a  rule,  the  males  of  this  species  mate  with  but  one 
female,  or  with  two  at  the  most,  but  instances  have  been 
recorded  where  single  males  mated  with  six  females,  and 
five  other  males  mated  with  three  females  each.  Polygamy 
is  exceptional  among  the  females.  In  August,  1894,  a 
female  moth,  at  the  insectary,  mated  with  three  males;  but 
nearly  all  females  reared  in  confinement,  as  well  as  those 
whose  mating  has  been  observed  in  the  field,  paired  with 
but  a  single  male. 

The  fact  that  a  male  imago  may  fertilize  several  females 
has  a  practical  bearing  on  the  work  of  destroying  the  gypsy 
moth.  It  would  seem  to  indicate  that  the  destruction  of  the 
males,  either  through  natural  or  artificial  agencies,  is  of  but 
little  importance. 

LEXGTH  OF   LIFE   OF   IMAGO. 

The  maximum  number  of  days  of  the  life  of  thirty-four 
females  which  had  not  mated  was  found  to  be  10,  the  mini- 
mum 1,  and  the  average  6.15  days.  The  maximum  number 
of  days  of  the  life  of  forty-two  females  which  mated  was 
found  to  be  12,  the  minimum  1,  and  the  average  7.69  days. 
The  actual  length  of  life  of  the  male  moth  is  hard  to  deter- 
mine, as  they  probably  live  much  longer  when  free  than  when 
kept  in  confinement.  Five  males  which  had  not  mated  lived 
respectively  6,  7,  8,  11  and  8  days. 


344  THE   GYPSY  MOTH. 

HABITS   or  FLIGHT. 

The  gypsy  moth  is  not  nocturnal,  and,  unless  disturbed, 
but  few  of  the  males  fly  before  9  A.M.  The  time  of  greatest 
activity  is  between  10  A.M.  and  3  or  4  P.M.,  after  which  time 
they  seldom  fly  voluntarily.  As  already  stated,  they  fly 
most  vigorously  on  warm  days,  and  in  a  zigzag  course. 

The  female  moth  has  never  been  seen  to  fly  in  this  coun- 
try, except  on  one  occasion,  and  that  was  after  the  laying 
of  the  eggs.  Mr.  F.  H.  Mosher,  one  of  our  most  reliable 
observers,  while  making  observations  in  a  colony  of  the 
gypsy  moth  in  the  forest  at  Woburn,  Mass.,  July  18,  1895, 
saw  a  female  gypsy  moth  that  had  finished  or  nearly  finished 
laying  her  eggs,  upon  being  disturbed  by  males,  drop  to  the 
ground  and  fly  about  twenty  feet,  striking  the  ground  and 
rising  again  at  distances  of  about  two  feet.  In  Europe,  C. 
Wingelmuller,  in  the  "  Wiener  Illustrirte  Garten-Zeitung," 
Jan.  15,  1890,  page  269,  says  that  "the  female  gypsy  moth 
does  not  shake  oif  her  sluggishness  even  during-  the  night, 
the  especial  time  of  her  activity  ;  and  a  short,  lazy  flight 
from  one  tree  to  another  close  by  is  the  most  that  she  accom- 
plishes." This  helplessness  is  only  on  account  of  her  body 
being  stored  with  eggs,  which  prevents  her  from  taking  a 
longer  flight.  I  have  tried,  again  and  again,  at  various 
times  during  the  day,  to  oblige  the  females  to  fly,  by  throw- 
ing them  into  the  air  and  also  by  knocking  them  off  from  the 
trees ;  and  in  every  case  they  only  fluttered  to  the  ground 
without  any  attempt  to  move  forward  by  using  their  wings. 
On  July  14,  1889,  I  was  in  the  zoological  gardens  in  Berlin, 
and  saw  the  gypsy  moths  in  great  abundance.  They  were 
then  in  the  imago  stage,  and  occasionally  females  fluttered 
down  from  the  trees  in  precisely  the  same  manner  that  they 
do  in  this  country  when  disturbed  by  the  males.  As  our 
employees  have  observed  the  habits  of  this  insect  at  all  hours 
of  the  day  and  night,  and  have  seen  no  real  flight  except  in 
the  case  above  mentioned,  and  as  the  statement  of  Wingel- 
muller seems  a  little  indefinite,  I  am  inclined  to  think  that 
the  female  gypsy  moth  never  voluntarily  flies,  nor  indeed 
can  she  do  so  before  laying  her  eggs,  because  of  the  enor- 
mous weight  she  would  have  to  sustain.  It  may  further  be 


ASSEMBLING.  345 

said  that,  although  the  wings  of  the  female  are  of  fair  size, 
they  are  not  nearly  as  firm  as  those  of  the  male,  and  it 
would  seem  that  by  disuse  they  have  become  weakened ; 
and,  if  the  present  conditions  are  continued  sufficiently  long, 
the  wings  of  the  female  gypsy  moth  may  suffer  the  same  fate 
as  those  of  the  female  of  the  white-marked  Tussock  moth 
(Plate  39,  Fig.  18). 

The  peculiar  zigzag  flight  of  the  male  may  be  the  result 
of  natural  selection.  As  the  female  does  not  fly,  the  male  is 
guided  to  her  by  the  odor  which  she  gives  off,  and  which  is 
disseminated  by  currents  of  air ;  and  it  is  evident  that  males 
flying  in  a  straight  line  would  not  meet  with  the  scent-laden 
currents  in  as  many  cases  as  those  which  fly  in  a  zigzag 
course.  It  is  therefore  probable  that  more  of  those  having 
a  tendency  to  an  irregular  course  in  flight  would  find  and 
mate  with  the  females,  and  thus  transmit  to  their  male 
offspring  a  like  tendency  to  this  particular  flight,  which,  in 
the  course  of  generations,  has  become  a  fixed  characteristic 
of  this  species. 

THE  ASSEMBLING  OF  THE  GYPSY  MOTH. 

It  is  a  well-known  fact  that  unfertilized  females  of  the 
gypsy  moth  are  able  to  attract  the  males  to  them  from  a 
greater  or  less  distance.  This  is  called  assembling,  and  this 
power  to  assemble  is  possessed  by  quite  a  large  number  of 
moths  more  or  less  nearly  related  to  the  gypsy  moth. 

As  has  been  previously  stated,  the  caterpillars  of  this 
insect  have  the  habit  of  spinning  down,  or  suspending  them- 
selves from  the  trees  on  which  they  feed,  especially  when 
disturbed ;  and  they  frequently  fall  upon  passing  teams  or 
animals,  and  are  carried  by  them  to  places  more  or  less 
remote.  If,  in  any  such  case,  caterpillars  should  be  carried 
into  an  uninfested  region,  and,  making  their  way  to  suitable 
food  plants,  should,  in  transforming,  give  rise  to  female 
moths,  there  would  be  little  or  no  danger  of  their  establish- 
ing a  new  colony,  unless  they  should  attract  male  moths 
from  the  infested  region,  and,  having  mated  with  them, 
should  therefore  lay  fertile  eggs. 

The  following  experiments  were  made  by  Mr.  A.  H.  Kirk- 
land,  assisted  by  Mr.  J.  P.  Hylan,  for  the  purpose  of  deter- 


346  THE   GYPSY  MOTH. 

mining,  as  fully  as  possible,  how  far  the  males  might  be 
assembled  by  the  females.  The  question  to  be  solved  was, 
from  how  great  a  distance  can  a  male  moth  recognize  and 
follow  up  the  scent  of  the  female  ?  There  are  many  condi- 
tions affecting  the  distance  over  which  assembling  may  be 
possible.  The  following  are  a  few  of  the  more  important :  — 

1.  The  place  in  which  the  female  emerges.    If  this  occurs 
in  a  stone  wall  or  rubbish  heap,  or  in  a  hollow  tree,  the  odor 
could  not  possibly  escape  and  be  diffused  as  fully  as  if  the 
moth  were  exposed  to  the  air  on  the  outside  of  the  tree,  and 
at  some  height  from  the  ground. 

2.  The  condition  of  either  the  male  or  female  after  emerg- 
ing.    If  the  female  is  strong  and  in  perfect  condition,  she 
will  assemble  more  males  than  a  female  partly  denuded.      If 
the  male  is  strong  and  active,  he  will,  of  course,  be  superior 
in  flight  and  action  to  one  partially  crippled  or  enfeebled. 

3.  The  direction  and  velocity  of  the  wind.     The  wind 
must  blow  from  the  place  where  the  female  emerges  toward 
some  place  where  male  moths  occur.    A  wind  of  high  velocity 
will  carry  the  odors  farther  than  a  light  breeze,  but,  at  the 
same  time,  offer  greater  resistance  to  the  flight  of  the  male 
while  following  up  the  scent. 

4.  Weather  and  temperature.     The  flight  of  the  males 
is  more  vigorous  on  bright,  warm  days  than  when  the  air  is 
cold  and  damp. 

5.  The  contour  of  the  land  and  whether  it  is  wooded  or 
not,  thus  forming  wind-breaks.     If  there  are  forests  or  hills 
between  the  female  in  question  and  the  males  to  be  attracted, 
they  will  interfere  with  the  direct  passage  of  currents  of  air 
carrying   the   odor,  so  that  males  may  fail  to  be  attracted 
from  much  shorter  distances  than  if  in  a  region  without  these 
obstructions. 

Details  of  the  Experiments. 

A  level  area  on  the  salt  marsh  between  Edgeworth  and 
Somerville,  entirely  free  from  obstructions,  was  selected  for 
the  scene  of  operations,  and  stations  were  established  from 
day  to  day,  according  to  the  direction  of  the  wind. 

Stations.  —  The  first  station  chosen  in  each  experiment 
was  the  one  where  one  or  more  females  were  to  be  located, 


ASSEMBLING.  347 

and  this  was  always  on  the  windward  side  of  the  marsh. 
The  females  were  enclosed  in  a  moth  trap  (Plate  54), 
which  was  painted  on  the  outside  with  a  mixture  of  castor 
oil  and  resin,  and  placed  a  few  feet  above  the  ground.  The 
second  station  was  established  directly  to  leeward  of  the 
first,  and  at  a  measured  distance  from  it.  In  many  cases  a 
third  and  even  a  fourth  station  was  established  at  a  known 
distance  from  the  first  and  other  intervening  stations.  It 
was  often  found  necessary  to  establish  three  or  even  more 
stations,  a  short  distance  apart,  on  the  arc  of  a  circle,  the 
radius  of  which  was  a  known  distance  from  the  trap,  to 
compensate  for  the  veering  of  the  wind,  which  sometimes 
carried  the  scent  of  the  female  out  of  a  direct  line  to  the 
stations  first  established. 

Marking  the  Males.  —  In  order  to  carry  on  this  work  and 
obtain  results  at  all  satisfactory,  it  was  necessary  to  adopt 
some  system  of  marking  the  males  which  were  to  be  liber- 
ated, in  such  a  way  as  to  enable  one  not  only  to  recognize 
them  afterwards,  but  also  to  determine  from  what  station 
they  came.  At  first  they  were  marked  by  cutting  a  small 
notch  in  a  certain  part  of  the  margin  of  the  wing,  with  fine 
scissors.  This  method,  while  not  apparently  injuring  them 
in  any  way,  was  objectionable,  because  of  its  being  a  muti- 
lation which  might  affect  the  results  more  or  less,  and 
therefore  it  was  abandoned  in  the  later  experiments,  and 
water-colors  were  used.  It  was  found  impossible  to  make 
the  colors  adhere  to  the  wings,  when  mixed  in  water;  but 
fifty  per  cent,  alcohol  was  found  to  mix  well  with  dry  car- 
mine colors,  and,  when  applied  to  the  wing,  made  a  tolerably 
permanent  mark.  There  was  no  difference  in  the  results 
obtained  from  moths  marked  in  the  two  ways.  In  marking, 
the  color  was  applied,  by  means  of  a  soft  brush,  to  a  par- 
ticular spot  on  the  wings,  a  different  mark  being  used  for 
each  station,  and  a  different  set  of  marks  each  day.  The 
male  moths  were  marked  and  boxed  each  morning,  the 
marks  recorded,  and  the  moths  taken  into  the  field.  The 
females  were  enclosed  in  the  cage  of  the  trap  at  station  No. 
1,  and  the  males  were  liberated  at  the  other  stations  accord- 
ing to  their  marks.  In  this  way  it  was  possible,  when  a 
male  was  taken  at  station  No.  1,  to  determine  from  which 


348  THE  GYPSY  MOTH. 

of  the  other  stations  it  came,  and  the  direct  distance  from 
that  station.  The  negative  results  in  so  many  of  the  experi- 
ments were  not  due  to  lack  of  care  or  attention  to  details, 
but  in  some  cases  to  a  change  of  wind  immediately  after  the 
liberation  of  the  males,  and  in  others  to  a  dying  out  of  the 
wind  before  the  males  had  reached  the  females.  Many  of 
the  male  moths,  as  is  common  with  them  when  handled, 
would  drop  to  the  ground  and  remain  in  the  grass  for  a  long 
time ;  and  it  was  found  necessary  to  liberate  a  number  of 
them  at  each  station,  in  order  to  increase  the  chance  of  meet- 
ing with  the  scent  from  the  female.  The  following  experi- 
ments were  made  in  July,  1895  :  — 

Experiment  No.  1. 

"Weather,  fair  and  clear.  Wind,  north-west;  average 
movement,  12  miles.  Two  traps,  containing  seven  female 
moths  each,  were  set  up  at  9.15  A.M.,  at  station  No.  1.  At 
station  2,  one-fourth  of  a  mile  to  leeward  of  the  first  station, 
eight  marked  male  moths  were  liberated  at  9.25  A.M.  At 
station  3,  one-half  a  mile  to  leeward  of  No.  1,  seven  marked 
male  moths  were  liberated  at  9.35  A.M.  Nothing  resulted 
from  this  experiment. 

^Experiment  No.  2. 

Weather,  fair.  Wind,  at  6.10  A.M.,  west;  from  10  A.M. 
to  3  P.M.,  east;  average  movement,  10  miles.  Two  traps, 
containing  six  female  moths  each,  were  set  up  at  10  A.M., 
ten  feet  from  the  ground.  At  station  2,  one  hundred  and 
fifty  yards  to  leeward,  nine  marked  male  moths  were  liber- 
ated at  10.15  A.M.  At  station  3,  half  a  mile  to  the  leeward 
of  station  1,  nine  marked  male  moths  were  liberated.  Four 
males  were  seen  flying  about  station  1,  but  only  one  was 
captured,  and  this  one  was  from  station  No.  3,  half  a  mile 
distant. 

Experiment  No.  3. 

Cloudy.  Wind,  south-west  to  west ;  average  movement, 
10  miles.  Two  traps,  containing  six  female  moths  each, 
were  set  up  at  station  1.  Seven  marked  male  moths  were 
let  loose  at  8.10  A.M.  from  station  2,  two  hundred  yards  to 
leeward  of  the  first  station,  and  at  8.20  A.M.  seven  marked 


ASSEMBLING.  349 

males  were  liberated  from  station  3,  half  a  mile  to  leeward 
from  station  1.  No  males  reached  the  first  station,  but  the 
rain  which  fell  from  11  A.M.  till  night  may  have  prevented 
the  males  from  flying. 

Experiment  No.  4. 

Weather,  fair.  Wind,  north  to  east ;  average  movement, 
10  miles.  Two  traps,  containing  six  females  each,  were  set 
up  at  10.30  A.M.  Forty  marked  males  were  liberated  at 
10.45  A.M.  from  station  2,  one-fourth  of  a  mile  from  the  first 
station,  and  thirty-eight  marked  males  were  liberated  at 
10.55  A.M.  from  station  3,  one-half  a  mile  from  the  first  sta- 
tion. At  3.30  P.M.  one  male  moth  appeared  in  the  vicinity 
of  the  first  station.  An  attempt  to  capture  it  was  unsuccess- 
ful. In  all  probability  it  came  from  either  station  2  or  3, 
since  there  were  no  infested  areas  in  the  direction  toward 
which  the  wind  was  blowing. 

Experiment  No.  5. 

Cloudy.  Wind,  east ;  average  movement,  9  miles.  Two 
traps,  containing  six  female  moths  each,  were  set  up  at  8 
A.M.  Nine  marked  males  were  liberated  at  8.30  A.M.,  one- 
fourth  of  a  mile  to  leeward  of  the  first  station,  and  nine 
marked  males  were  liberated  at  9  A.M.,  half  a  mile  to  lee- 
ward of  station  1.  None  of  these  males  reached  station  1. 

Experiment  No.  6. 

Damp  and  cloudy,  with  light  rains  at  intervals  until  2  P.M. 
Wind,  north-east ;  average  movement,  6  miles.  One  trap, 
containing  a  single  female  moth,  was  set  up  at  1.45  P.M. 
Six  marked  males  were  liberated  at  2.10  P.M.,  427  yards 
to  leeward  of  the  first  station,  and  fifty  marked  males 
were  liberated  at  2.30  p.M.r  at  station  3.  This  station  was 
located  713  yards  to  leeward  of  the  first  station.  At  3.30 
P.M.  one  male  from  station  2  reached  the  trap,  and  at  4.15 
P.M.  one  from  station  3. 

Experiment  No.   7. 

Fair.  Wind,  north-west ;  average  movement,  12  miles. 
Two  traps,  containing  twelve  female  moths  each,  were  set  up 


350  THE  GYPSY   MOTH. 

at  8  A.M.  At  station  2,  one-fourth  of  a  mile  to  leeward  of 
station  1,  six  marked  males  were  liberated  at  8.30  A.M.,  and 
at  2  P.M.  seven  more  males  were  liberated  at  this  station. 
At  station  3,  one-half  mile  to  leeward  of  station  1,  six 
marked  males  were  liberated  at  8.45  A.M.,  and  at  2.15  P.M. 
eight  others  similarly  marked  were  also  allowed  to  escape 
at  this  station.  There  were  no  results  from  this  experiment. 

Experiment  No.  8. 

Fair.  Wind,  from  nearly  all  directions ;  average  move- 
ment, 5  miles.  Two  traps,  containing  six  female  moths 
each,  were  set  up  at  8.30  A.M.  At  station  No.  2,  one-fourth 
of  a  mile  to  leeward  of  station  1,  eight  marked  males  were 
liberated  at  9.50  A.M.  At  station  3,  one-half  mile  to  lee- 
ward of  station  1,  six  marked  males  were  liberated  at  9.08 
A.M.,  and  six  other  males  similarly  marked  were  liberated  at 
a  distance  of  sixteen  yards  to  the  right  of  station  1.  One 
male  moth  from  station  2  returned  at  10.30  A.M.  The  wind 
shifted  to  east  and  south-west,  and  at  1.30  a  heavy  rain  pre- 
vented all  further  work. 

The  data  concerning  the  direction  and  wind  movement, 
given  in  these  experiments,  were  kindly  furnished  by  Mr.  J. 
"W.  Smith,  the  Boston  local  forecast  official,  and,  as  the  place 
where  the  experiments  were  performed  was  within  four  miles 
of  the  Boston  observatory,  the  figures  in  all  probability  are 
approximately  accurate  for  the  locality. 

Remarks  on  the  Above  Experiments. 
These  experiments  show  that,  under  favorable  conditions, 
female  gypsy  moths  will  assemble  males  from  various  dis- 
tances up  to  half  a  mile,  and  it  is  possible  that  they  might 
have  been  attracted  from  somewhat  greater  distances  had 
males  been  liberated  in  larger  numbers  from  stations  more 
remote  from  the  female.  It  must  be  borne  in  mind  that 
these  experiments  were  conducted  under  what  would  seem 
to  be  the  most  favorable  conditions,  namely,  upon  a  level 
area,  where  a  sweep  of  the  wind  could  be  obtained ;  yet  it 
may  be  possible  that  what  was  gained  by  the  favorable  con- 
ditions was  in  a  measure  offset  by  a  slight  weakening  of  the 
males  caused  by  the  handling  necessary  while  marking  them. 


ASSEMBLING.  351 

As  shown  by  these  records,  males  were  assembled  427  yards 
(see  experiment  No.  6),  440  yards  (see  experiment  No.  8), 
713  yards  (see  experiment  No.  6)  and  880  yards  (see  experi- 
ment No.  2). 

A  series  of  experiments,  to  determine  the  manner  in  which 
the  male  gypsy  moth  recognizes  the  presence  of  the  female, 
was  made  at  the  insectary  and  in  the  field,  with  the  follow- 
ing results :  — 

Experiment  No.  9. 

July  25.  To  determine  the  effect  of  alcohol  upon  the 
antennae,  as  the  shellac  to  be  used  later  was  dissolved  in 
alcohol,  the  antennae  of  a  male  moth  were  thoroughly  bathed 
in  ninety-three  per  cent,  alcohol  at  10.50  A.M.  The  first 
effect  of  this  application  might  well  be  called  a  complete 
intoxication.  The  moth  lay  for  two  or  three  minutes  flat 
on  the  table  without  stirring.  At  10.53  he  began  to  move, 
but  had  only  partial  control  of  his  limbs,  and  travelled  with 
unsteady  gait  a  short  distance  on  the  bench.  By  degrees  he 
completely  recovered  his  normal  condition,  and  at  1.15  P.M. 
he  mated  with  a  female  in  a  normal  manner. 

Experiment  No.  10. 

July  30.  At  9.30  A.M.,  the  wings  of  four  unfertilized 
females  were  completely  covered  with  shellac,  after  which 
the  moths  were  placed  in  the  experimental  room,  and  two 
males  in  normal  condition  were  liberated.  At  10  A.M., 
a  female  attracted  and  mated  with  one  of  the  males.  At 
10.50  A.M.,  the  other  male  was  attracted  to  a  second  female, 
but  did  not  mate.  At  11.30  A.M.,  the  same  male  was 
attracted  to  a  third  female,  with  the  same  results  as  in  the 
preceding  case.  At  3  P.M.,  one  of  these  females  attracted  a 
male,  which  mated  with  her  at  once. 

Experiment  No.  11. 

July  30.  At  9.30  A  M.,  the  dorsal  surface  of  four  females 
(with  the  exception  of  the  wings)  was  coated  with  shellac 
varnish,  the  moths  then  being  introduced  into  the  experi- 
mental room  with  a  number  of  normal  males.  At  10.30 
A.M.,  one  female  mated  with  a  male.  At  11.40  a  female 


352  THE   GYPSY  MOTH. 

attracted  a  male,  but  did  not  succeed  in  mating.  At  12  M., 
a  female  attracted  a  male,  with  the  same  result  as  in  the  pre- 
ceding case. 

Experiment  No.  12. 

July  30.  At  9.30  A.M.,  the  head  and  thorax  of  four 
females  were  completely  coated  with  shellac  varnish,  after 
which  operation  the  moths  became  quite  stupid  and  one  of 
them  seemed  apparently  dead.  At  4.30  P.M.,  one  of  the 
females  mated  with  a  male,  but  none  of  the  others  mated. 

Experiment  No.  13. 

July  30.  At  10.15  A.M.,  four  unfertilized  females  were 
coated  with  varnish  along  the  sides  of  the  thorax  and  abdo- 
men. They  were  then  placed  in  a  wire-gauze  can,  which 
was  attached  to  a  tree,  in  the  Woburn  colony,  at  a  height  of 
about  six  feet  from  the  ground.  This  trap  was  visited  by 
thirty-eight  males  from  10.15  A.M.  to  3  P.M. 

Experiment  No.  14. 

July  30.  Another  can,  containing  four  unfertilized  females 
in  normal  condition,  and  used  as  a  check,  was  visited  by 
thirty-eight  males  from  10.15  A.M.  to  3  P.M. 

Experiment  No.  15. 

July  30 .  Another  can ,  containing  four  unfertilized  females , 
whose  wings  were  covered  on  both  surfaces  with  shellac,  was 
exposed  under  similar  conditions.  This  trap  was  visited  by 
seventy-six  males  from  10.15  A.M.  to  3  P.M. 

Experiment  No.  16. 

July  30.  A  can  containing  four  unfertilized  females,  with 
the  whole  of  the  body,  except  the  wings,  covered  with  shel- 
lac, was  exposed  under  the  same  conditions.  This  trap  was 
visited  by  only  one  male.  A  check  can  containing  four  un- 
fertilized females,  in  normal  condition,  exposed  in  the  same 
manner  and  at  the  same  place  as  those  in  the  preceding 
experiments,  to  determine  what  would  be  the  normal  rate  of 
assembling,  was  visited  by  seventy-seven  males  from  10.15 
A.M.  to  4  P.M. 


ASSEMBLING.  353 


Experiment  No.  17. 

August  1.  A  can  containing  four  unfertilized  females, 
with  the  last  three  segments  of  the  abdomen  coated  entirely 
with  shellac,  was  exposed  as  in  the  previous  experiments, 
and  was  visited  by  twelve  males  from  10.15  A.M.  to  4  P.M. 

Experiment  No.  18. 

August  1.  Another  can,  containing  four  unfertilized 
females,  which  were  coated  with  shellac  over  the  whole 
body,  with  the  exception  of  the  three  posterior  segments, 
was  exposed  under  the  same  conditions  as  in  the  preced- 
ing experiments,  and  was  visited  by  twenty-six  males  from 
10.15  A.M.  to  4  P.M. 

Experiment  No.  19. 

August  1.  A  can  containing  four  unfertilized  females, 
with  the  tips  of  their  abdomens  covered  with  shellac,  so  as 
to  close  the  external  openings  of  the  body,  was  exposed 
under  the  same  conditions  as  in  the  preceding  experiments, 
and  was  visited  by  eleven  males  from  10.15  A.M.  to  4  P.M. 

Experiment  No.  20. 

August  2.  A  single  unfertilized  female,  in  normal  con- 
dition, was  placed  in  a  small  cardboard  box,  having  a  cheese- 
cloth top,  and  exposed  on  the  branch  of  a  tree,  at  a  distance 
of  five  feet  from  the  ground.  This  box  was  visited  by 
twenty-eight  males  from  10.30  A.M.  to  3  P.M. 

Experiment  No.  21. 

August  2.  A  wire-gauze  can,  containing  an  unfertilized 
female  that  had  been  denuded  of  hair,  but  whose  wings  were 
in  a  normal  condition,  was  exposed  under  the  same  con- 
ditions as  in  the  preceding  experiments,  and  was  visited  by 
thirteen  males  from  10.30  A.M.  to  1  P.M. 

Experiment  No.  22. 

August  2.  This  experiment  was  conducted  under  the  same 
conditions  and  at  the  same  time  as  preceding  experiments, 


354  THE  GYPSY  MOTH. 

except  that  the  can  contained  a  female  whose  wings  were 
removed  close  to  the  body.  This  trap  was  visited  by  four- 
teen males  from  10.30  A.M.  to  3  P.M. 

Experiment  No.  23. 

August  6.  A  female,  with  all  appendages  and  down  re- 
moved, was  suspended  in  a  mosquito-net  bag  in  the  centre  of 
a  colony  in  Hawke's  woods,  Saugus.  She  received  no  visits 
from  males  up  to  5  P.M. 

Experiment  No.  24. 

August  6.  Same  place  as  above.  At  10.45  A.M.,  a  de- 
nuded female  was  suspended  in  a  mosquito-bar  box  from  a 
tree,  at  a  height  of  five  feet  from  the  ground.  At  5  P.M.  she 
had  received  no  visits  from  males. 

Experiment  No.  25. 

July  25.  At  1.45  P.M.,  the  antennae  of  two  male  moths 
were  covered  with  shellac  varnish.  This  produced  no  ap- 
parent effect  upon  the  moths.  The  males  were  kept  in  close 
proximity  to  females  during  the  remainder  of  the  afternoon, 
but  none  of  them  attempted  to  mate.  July  25.  At  1.45 
P.M.,  the  antennae  of  two  males  were  covered  with  a  coating 
of  shellac,  and  the  moths  were  then  placed  in  a  small  card- 
board box  with  four  unfertilized  females.  July  26,  at  7 
A.M.,  the  moths  had  not  mated. 

Experiment  No.  26. 

July  25.  At  1.45  P.M.,  the  antennae  of  a  male  moth, 
which  had  just  begun  to  mate  with  a  female,  were  covered 
with  shellac  varnish.  This  apparently  produced  no  effect, 
as  the  male  did  not  leave  the  female  until  2.20  P.M. 

Experiment  No.  27. 

July  25.  At  3.48  P.M.,  a  fresh,  vigorous  male  was 
deprived  of  both  fore  legs  and  then  placed  on  the  experi- 
mental bench  near  a  female.  The  odor  of  the  female  was 
driven  towards  him  by  the  use  of  a  fan,  and  he  at  once  recog- 
nized her  presence,  and  at  3.51  P.M.  the  moths  mated. 


ASSEMBLING.  355 


Experiment  No.  28. 

July  26.  At  8.50  A.M.,  one  male  moth,  with  three  legs 
removed,  was  placed  on  the  experimental  bench  three  feet 
from  four  unfertilized  females.  At  9  A.M.,  he  flew  to  the 
partially  drawn  curtain  and  remained  there  until  10.45,  when 
he  flew  down  from  the  window  and  mated  with  a  female. 
At  11  A.M.  his  antennae  were  cut  off,  but  this  did  not  pro- 
duce any  appreciable  effect.  They  remained  together  until 
11.30.  After  leaving  the  female,  he  remained  inactive  dur- 
ing the  rest  of  the  day. 

Experiment  No.  29. 

July  26.  At  8.50  A.M.,  a  male  moth,  with  its  wings 
removed,  was  placed  on  the  experimental  bench  at  a  distance 
of  three  feet  from  four  unfertilized  females.  At  10.20  A.M., 
he  approached  rapidly  within  two  inches  of  the  females,  but 
eventually  crawled  away  to  a  distance  of  three  feet  from 
them.  At  1.40  P.M.,  he  was  placed  near  a  female  on  the 
bench,  but  after  a  few  minutes  went  away  from  her.  At 
2.05,  he  was  placed  within  one  foot  of  a  female,  and  after 
crawling  slowly  toward  her,  mated  with  her. 

Experiment  No.  30. 

July  26.  At  8.50  A.M.,  a  male  moth  with  both  antennae 
removed  was  placed  three  feet  from  four  unfertilized  females. 
At  9,  he  had  crawled  a  distance  of  one  foot  toward  the 
females.  He  remained  quiet  until  11  A.M.,  when  he  was 
placed  close  to  a  female  moth.  He,  however,  paid  no  atten- 
tion to  her,  and,  up  to  5  P.M.,  made  no  attempt  to  mate. 

^Experiment  No.  31. 

July  26.  At9.28A.M.,  the  antennae  of  a  small  male  were 
coated  with  shellac  and  he  was  placed  on  the  experimental 
bench,  at  a  distance  of  two  feet  from  a  number  of  females. 
At  11.30,  he  had  made  no  effort  to  mate  with  any  of  them. 
He  was  then  placed  on  a  box  containing  a  large  number 
of  unfertilized  females,  but  showed  no  animation.  Other 
males,  with  their  antennae  not  coated,  were  continually  hov- 


356  THE   GYPSY  MOTH. 

ering  about  the  box.     The  male  in  question  remained  quiet 
until  5  P.M. 

Experiment  JVb.  32. 

July  26.  At  3  P.M.,  the  eyes  of  three  male  moths  were 
covered  with  shellac,  and  they  were  then  placed  within  two 
feet  of  two  mature,  unfertilized  females.  At  3.05,  one  male 
flew  to  the  females  and  attempted  to  mate,  but  was  unsuc- 
cessful. At  3.25,  another  male  approached  the  females,  in 
the  same  manner,  but  with  no  better  success,  but  at  3.35 
two  of  the  males  were  successful  in  mating  with  two 
females. 

Experiment  JVb.  33. 

July  27.  At  9.30  A.M.,  two  males  with  eyes  and  a  part 
of  the  head  covered  entirely  with  shellac  were  placed  on  the 
experimental  bench,  three  feet  from  four  unfertilized  females. 
At  12  M.,  one  of  these  males  began  to  fly  about,  and  at  1 
P.M.  he  was  found  mating  with  a  female  five  feet  from  the 
place  where  he  was  at  noon.  At  1.45  he  left  the  female,  and 
at  this  same  time  the  other  male,  whose  eyes  had  been  cov- 
ered with  shellac,  mated  with  a  female  and  remained  with 
her  up  to  the  time  the  experiment  closed,  at  5  P.M. 

From  the  preceding  experiments  the  following  conclusions 
may  be  drawn  :  — 

1.  Coating  the  abdomen  of  the  female  with  varnish  or 
denuding  it  of  hair  deprives  her,  in  a  great  measure,  of  the 
power  to  assemble  males.     The  amount  of  assembling  which 
takes  place  under  these  conditions  varies  inversely  with  the 
amount  of  body  surface  coated  or  denuded. 

2.  The  presence  or  absence  of  wings  in  either  sex  does 
not  greatly  influence  the  assembling  process. 

3.  The  sense  of  sight  is  not  necessary  to  the  operations 
of  assembling. 

4.  The  antennae  are  absolutely  necessary  to  the  male  in 
locating  the  female,  and  without  them  assembling  is  impos- 
sible.    It  is  a  well-known  fact  that  the  males  of  this  species 
coming  from  any  distance  always   approach  from  the  lee- 
ward side  of  the  female,  thus  apparently  indicating  that  the 
assembling  is  the  result  of  an  odor  given  off  by  the  female, 
and  carried  bv  the  wind. 


EXPLANATION  OF  PLATE  53. 


Drawn  by  J.  H.  EMERTON. 


1.  Calosoma  frigidum  Kirby,  natural  size. 

2.  Menecles  insertus  (Say),  "         " 

3.  Podisus  cynicus  (Say),  "         " 

4.  Podisus  serieventris  Uhl., 

5.  Polities  pallipes  St.  Farg.,  "         " 

6.  Theronia  melanocephala  (Brulle),      "          " 

7.  Pimpla  pedalis  Cress.,  female,  "         " 

7  a.          "  "  "       male,  "         " 

8.  Pimpla   tenuicornis  Cress.  X  4. 

8  a.         "  "  "  natural  size. 

9.  Formica  subsericea  Say,  worker  X  4. 

9  a.  "  "  "  "  natural  size. 
10.  Diglochis  omnivorus  (Walk.),  female  X  8. 

10  a.  "  "  "  "       natural  size. 

10  b.  "  "  "        male  X  8. 

loc.  "  "  "  "      natural  size, 

n.  Achatoneura  fernaldi  Williston,  female  X  4. 

11  a.  "  "  "  "      natural  size, 
nb.               "                  "              "         foot  of  female, 
nc.               "                  "               "  "       male. 

11  d.  "  "  "         face  of  female, 
ne.               "                  "              u  "       male. 

12.  Elachiptera  dispar  Williston  X  8. 

12  a.  "  "  "         natural  size. 

13.  Phlaothrips  sp.  ?  X  32. 

14.  Nothrus  sp.?  X  32. 

15.  Trombidium  bulbipes  Pack.  X  32. 


ASSEMBLING.  357 

Concerning  the  assembling  process  in  the  Bombycidae,  the 
late  Prof.  C.  V.  Riley  wrote  as  follows:  "The  power  of 
assembling  among  certain  moths,  for  instance,  especially 
those  of  the  family  Bombycidae,  is  well  known  to  entomolo- 
gists, and  many  remarkable  instances  are  recorded.  .  .  . 
Now,  in  the  moths  of  this  family  the  male  antennae  are  elab- 
orately pectinate,  the  pectinations  broad  and  each  branch 
minutely  hairy.  These  feelers  vibrate  incessantly,  while  in 
the  female,  in  which  the  feelers  are  less  complex,  there  is  a 
similar  movement  connected  with  an  intense  vibration  of  the 
whole  body  and  of  the  wings.  There  is,  therefore,  every 
reason  to  believe  that  the  sense  is  in  some  way  a  vibratory 
sense,  as,  indeed,  at  base  is  true  of  all  senses ;  and  no  one 
can  study  the  wonderfully  diversified  structure  of  the  an- 
tennas in  insects,  especially  in  males,  as  very  well  exemplified 
in  some  of  the  commoner  gnats,  without  feeling  that  they 
have  been  developed  in  obedience  to,  and  as  a  result  of, 
some  such  subtle  and  intuitive  power,  as  this  of  telepathy. 
Every  minute  ramification  of  the  wonderfully  delicate  feelers 
of  the  male  mosquito,  in  all  probability,  pulsates  in  response 
to  the  piping  sounds  which  the  female  is  known  to  produce, 
and  doubtless  through  considerable  distance  "  ("Insect  Life," 
Vol.  VII,  page  39). 

In  view  of  the  fact  that  the  males  of  the  gypsy  moth  will 
assemble  nearly  as  readily  to  empty  boxes,  bags,  etc.,  in 
which  females  of  the  species  have  been  previously  confined, 
as  to  the  females  themselves,  we  are  led  to  believe  that  with 
this  insect,  at  least,  the  process  is  one  depending  upon  the 
sense  of  smell  alone.* 

ON  TRAPPING  MALES. 

The  following  experiments  were  made  under  my  direction 
by  Mr.  H.  N.  Reid  in  1893,  for  the  purpose  of  determining 
whether  it  is  possible  to  trap  the  males  of  the  gypsy  moth, 
in  any  infested  region,  to  such  an  extent  that  there  would  not 
be  enough  left  to  mate  with  any  considerable  number  of 
females,  so  that  a  large  proportion  of  the  females  would  be 
compelled  to  lay  infertile  eggs,  and  therefore  greatly  reduce 

*  In  one  case  males  were  found  to  visit  an  empty  pasteboard  box  which  had  con- 
tained female  moths  three  days  before. 


358  THE  GYPSY  MOTH. 

the  number  of  gypsy  moths  in  that  locality  the  following 
season. 

For  this  purpose  wooden  boxes,  12  by  8  by  3  inches, 
were  made,  without  top  or  bottom,  these  being  covered  with 
brass  wire  gauze.  A  hole  was  bored  in  one  end  for  the  in- 
troduction of  the  female  moths,  and  this  was  closed  by  a 
cork.  Several  different  substances  were  used  on  these  traps, 
to  capture  the  males  when  they  flew  against  them,  as  mo- 
lasses, raupenleim,  sticky  fly-paper,  ejtc.  Molasses  proved 
of  no  value,  as  it  ran  too  easily,  and  was  not  sticky  enough. 
The  raupenleim  was  not  sticky  enough,  and  soon  dried  on 
the  outside,  so  that  it  would  not  hold  the  males  when  they 
flew  against  it.  Sheets  of  sticky  fly-paper,  with  holes  9  by 
4  inches  cut  from  the  centre,  were  tacked  over  the  gauze ; 
these  proved  very  efficient  in  securing  and  holding  the 
males,  but  it  was  necessary  to  replace  them  with  fresh  ones 
frequently,  and,  to  avoid  this,  they  were  painted  over  with  a 
preparation  of  castor  oil  and  resin,  which  proved  to  be  bet- 
ter for  the  purpose  required  than  the  original  fly-paper. 
When  a  trap  was  first  put  up  a  sheet  of  fly-paper  was 
tacked  on  it,  and  each  time  the  trap  was  visited  the  cap- 
tured males  were  removed  and  the  paper  recoated  so  far  as 
necessary.  This  gum  was  found  to  keep  in  good  condition 
for  several  days,  unless  a  large  number  of  males  were  caught 
in  it,  or  the  trap  was  in  a  very  dusty  place.  Even  when  the 
males  were  not  caught  the  first  time  they  touched  the  paper, 
they  were  so  persistent  that  they  would  immediately  fly 
against  it  again,  and  be  caught  in  a  few  minutes. 

The  fly-paper  was  removed  from  one  trap  (No.  14)  after  a 
few  days,  and  a  pan  of  water  with  a  little  kerosene  on  the 
top  of  it  was  suspended  directly  beneath  the  trap.  On  ac- 
count of  the  rapidity  with  which  the  males  fly,  and  the  light- 
ness with  which  they  struck  the  trap,  it  was  not  expected 
that  they  would  be  caught  in  the  kerosene ;  but,  being  very 
persistent,  in  trying  to  go  under  the  trap  from  one  side  to 
the  other  they  came  in  contact  with  the  kerosene  and  were 
destroyed.  This  plan  was  not  very  satisfactory,  not  only 
on  account  of  the  expense,  but  also  because  the  kerosene  and 
water  were  so  frequently  spilled  by  the  wind. 

To  obtain  "  bait"  for  these  traps,  it  was  found  better  to 


TRAPPING   MALES.  359 

collect  the  female  pupas  and  allow  them  to  emerge  in  con- 
finement, because  in  this  way  the  matter  could  be  controlled 
more  successfully  than  in  any  other.  It  was  also  found  that 
the  traps  attracted  best  when  placed  but  a  few  feet  above  the 
ground. 

Fifteen  traps  were  used  during  these  experiments.  No.  7 
was  removed  after  six  days,  to  be  placed  elsewhere,  as  noth- 
ing was  captured  on  it  up  to  that  time.  No.  14  had  sticky 
fly-paper  on  it  the  first  five  days,  during  which  time  it 
caught  two  hundred  males.  The  fly-paper  was  then  removed, 
and  a  pan  containing  the  water  and  kerosene  was  suspended 
an  inch  or  two  below  the  trap.  During  the  next  twelve  days 
sixty-five  males  were  captured  in  the  pan.  The  traps  were 
put  out  from  July  31  to  August  10,  and  were  taken  in  from 
August  19  to  August  30.  The  records  of  the  traps  are 
given  below :  — 

No.  1  was  put  out  July  31,  and  taken  in  August  19,  having 
captured  82  males. 

No.  2  was  put  out  July  31,  and  taken  in  August  19,  having 
captured  34  males. 

No.  3  was  put  out  August  1,  and  taken  in  August  28,  having 
captured  175  males. 

No.  4  was  put  out  August  1,  and  taken  in  August  28,  having 
captured  87  males. 

No.  5  was  put  out  August  2,  and  taken  in  August  30,  having 
captured  36  males. 

No.  6  was  put  out  August  2,  and  taken  in  August  25,  having 
captured  88  males. 

No.  7  was  put  out  August  2,  and  taken  in  August  8,  having 
captured  nothing. 

No.  8  was  put  out  August  8,  and  taken  in  August  30,  having 
captured  167  males. 

No.  9  was  put  out  August  8,  and  taken  in  August  26,  having 
captured  37  males. 

No.  10  was  put  out  August  8,  and  taken  in  August  30,  having 
captured  85  males. 

No.  11  was  put  out  August  8,  and  taken  in  August  26,  having 
captured  213  males. 

No.  12  was  put  out  August  8,  and  taken  in  August  28,  having 
captured  131  males. 


360  THE  GYPSY  MOTH. 

No.  13  was  put  out  August  9,  and  taken  in  August  30,  having 
captured  163  males. 

No.  14  was  put  out  August  10,  and  taken  in  August  30,  having 
captured  265  males. 

No.  15  was  put  out  August  10,  and  taken  in  August  28,  having 
captured  208  males. 


Omitting  No.  7,  which  remained  out  but  a  few  days,  the 
whole  number  of  males  taken  by  all  the  traps  was  1,771. 
The  smallest  number  taken  by  any  one  of  them  was  34,  the 
largest  number  was  265  and  the  average  126.5. 

During  the  months  of  July  and  August,  1894,  these  ex- 
periments were  repeated  by  Mr.  F.  C.  Schrader  and  four 
other  assistants.  One  hundred  and  ninety-one  traps  were 
put  up  in  the  worst  infested  districts  of  Maiden,  Medford 
and  Everett,  and  kept  in  working  order  during  the  time 
that  the  males  were  flying.  The  traps  were  visited  every 
day,  fresh  gum  applied  when  necessary,  new  females  put 
into  the  traps  as  often  as  needed,  and  careful  records  were 
kept  of  the  results.  The  trapping  season  began  July  19, 
and  closed  August  13.  Two  different  styles  of  traps  were 
used.  The  first  kind  was  made  of  two-quart  tin  varnish 
cans,  from  each  of  which  was  suspended,  about  two  inches 
below  it,  a  tin  base  9  by  12  inches,  dished,  soasto«lope 
from  the  edges  toward  the  centre,  and  attached  by  two  strips 
of  tin  to  a  loop  on  each  of  the  narrow  sides  of  the  can.  A 
strip  of  tin  was  removed  from  each  side  of  the  can,  and  this 
was  replaced  by  brass  wire  gauze.  The  unfertilized  females 
were  placed  in  the  can,  through  the  hole  at  the  top,  which 
was  kept  closed  by  a  cork  stopper.  The  traps  were  sus- 
pended from  branches  of  trees  by  hooks  eight  inches  long, 
attached  to  the  handle  of  the  cans. 

The  other  kind  was  a  four-leaved  wooden  trap,  commonly 
called  the  "Shaw"  trap  (Plate  54),  devised  by  Mr.  H.  J. 
Shaw.  It  consisted  of  a  horizontal  base  board  of  half-inch 
lumber,  one  foot  square,  with  narrow  grooves  at  right  angles 
across  the  middle  of  the  upper  side.  Two  thin  boards,  twelve 
inches  wide  and  seven  inches  high,  notched  together  in  the 
middle  at  right  angles,  were  secured  in  the  grooves  in  the 
base  board,  thus  forming  four  vertical  wings.  An  opening 


TRAPPING  MALES.  361 

was  cut  in  the  lower  edge  of  the  vertical  boards  at  the 
centre,  and  in  this  opening  was  secured  a  cylindrical  wire- 
gauze  cage,  three  inches  in  diameter  and  height,  and  with  a 
convex  tin  top  and  bottom.  The  unfertilized  females  were 
placed  in  this  cage  through  a  round  hole  in  the  top,  which 
was  kept  closed  by  a  cork.  The  trap  was  suspended  by 
means  of  a  hook  fitting  into  a  wire  loop  at  the  centre  of  the 
top  of  the  vertical  wings.  Several  other  kinds  of  traps  of 
various  patterns  were  tried,  but  none  proved  so  satisfactory 
as  the  two  described  above ;  and  of  these  the  four-leaved 
wooden  trap  proved  to  be  the  best,  as  it  allowed  the  females 
to  be  exposed  to  the  air  on  all  sides,  and  also  because  it  pre- 
sented a  greater  area  of  the  sticky  surface.  The  majority  of 
the  males  were  caught  on  the  base  boards  of  the  traps,  the 
greater  number  invariably  being  taken  on  the  leeward  side. 
The  ' '  bait "  used  in  all  of  these  traps  was  unfertilized 
female  moths  bred  from  pupae  in  confinement,  though  the 
pupae  themselves,  and  dead  and  fertilized  females,  were  also 
tried  for  the  purpose  of  ascertaining  whether  they  would 
attract  the  males.  It  was  found  advantageous,  when  keep- 
ing pupae  in  confinement,  to  moisten  them  with  a  fine  spray 
of  water  from  time  to  time,  to  keep  them  from  drying  up  so 
much  as  to  prevent  them  from  emerging.  The  "bait"  in 
the  traps  was  renewed  as  often  as  necessary.  The  best 
means  of  carrying  the  newly  emerged  females  was  found  to 
be  a  cloth-lined  box,  as  they  would  cling  to  the  lining,  and 
could  be  transported  in  this  way  with  little  or  no  injury. 
The  traps  were  painted  over  with  a  sticky  gum  composed  of 
sixty  per  cent,  of  crude  resin  and  forty  per  cent,  of  crude 
castor  oil.  The  resin  and  oil  were  melted  together,  and 
applied,  while  warm,  to  the  traps  by  means  of  a  flat  varnish 
brush,  care  being  taken  not  to  put  the  gum  on  the  gauze. 
Most  of  the  traps  required  repainting  about  every  second 
day,  though  some  required  it  oftener.  A  small  pointed 
trowel  was  used  in  removing  the .  captured  males  from  the 
glue,  and  a  pole  with  a  small  hook  at  the  end  was  used  in 
removing  and  replacing  the  traps  in  the  trees.  The  trapping 
operations  were  closed  August  13,  for  lack  of  "  bait,"  and 
also  because  so  few  males  were  then  captured  that  it  did  not 
seem  wise  to  continue  the  work. 


362  THE  GYPSY  MOTH. 

It  was  repeatedly  demonstrated,  in  different  towns  and 
with  different  traps,  that  they  can  be  handled  much  more 
easily  and  will  capture  more  males  when  hung  low,  or  placed 
near  the  ground,  than  when  they  are  placed  high  in  the  trees. 
The  gum,  when  made  in  the  proportion  given  above,  runs  and 
drips  in  hot  weather  and  in  the  warm  sunshine,  more  on  the 
tin  than  on  the  wooden  traps,  so  that  great  care  was  required 
in  placing  them  in  certain  localities  near  residences,  lest  the 
dropping  gum  should  do  harm.  The  adhesive  power  of  this 
gum  is  remarkable.  Two  young  birds  were  caught  on  the 
foot  board  of  the  tin  traps  in  Maiden.  They  were  both  dead 
when  found,  and  showed  evidence  of  desperate  efforts  to 
extricate  themselves.  In  the  struggle  they  had  pulled  out  a 
large  quantity  of  feathers,  and,  in  the  case  of  a  half-grown 
English  sparrow,  which  lay  upon  its  side  with  the  head 
directed  from  the  trap,  the  feathers  adhered  so  firmly  that 
the  bird  could  not  be  pulled  off  without  tearing  the  body 
apart.  Careful  observations  showed  that  at  least  ninety  per 
cent,  of  the  male  moths  were  captured  on  the  foot  board.  It 
was  also  found  that  where  the  moths  are  abundant  the  traps 
can  be  used  advantageously  within  ten  rods  of  each  other,  or 
hi  adjacent  lots. 

The  essential  point  for  the  successful  working  of  a  moth 
trap  is  to  have  the  female  well  exposed  on  all  sides,  so  that 
the  wind  may  pass  freely  over  her  body,  and  carry  the  odors 
away  without  obstruction  in  any  direction  that  the  air  may 
be  moving ;  and,  at  the  same  time,  she  should  be  sufficiently 
protected  to  insure  her  existence  as  long  as  possible.  The 
average  length  of  life  of  unfertilized  female  moths,  in  the 
wooden,  four-leaved  traps,  was  seven  days.  One  female 
moth,  put  into  the  trap  July  31,  was  alive  August  9,  but 
was  dead  at  the  time  of  the  next  visit,  August  11.  Another 
female  was  put  into  a  trap  August  1,  and  died  August  11. 
In  some  cases  the  moths  put  into  the  traps  were  caught  in 
the  gum,  which  worked  in  at  the  bottom  of  the  cans,  and 
died  in  a  day  or  two.  In  the  tin  traps  the  female  moths  did 
not  live  more  than  two  or  three  days,  and  those  in  the  old 
wooden  box  traps  used  the  year  previous  did  not  live  any 
longer,  seldom  exceeding  two  days. 

In  some  instances,  when  there  were  no  unfertilized  females 


, 


• 


Female  moths  depositing  their  egg-clusters  on  the  trunk 
of  an  oak  tree,  Saugus,  1895. 


OVIPOSITION.  363 

for  "  bait,"  fertilized  moths,  dead  moths  or  female  pupae 
were  used.  The  fertilized  females  attracted  the  males  in 
about  half  the  cases  where  they  were  used.  Of  eight  traps 
"  baited  "  with  fertilized  females,  three  caught  nothing,  two 
caught  one  each,  two  caught  two  each  and  one  caught  four- 
teen, being  an  average  of  two  and  one-half  each.  The  aver- 
age catch  of  the  same  traps,  "baited"  with  unfertilized 
females,  was  twenty  and  eight-tenths  each.  In  nineteen  of 
the  traps  dead  females  were  used  at  times,  but  they  proved  to 
be  of  little  value,  for  only  five  out  of  the  nineteen  attracted 
any  males.  The  total  number  of  females  used  was  twenty- 
three,  and  only  twenty-four  males  were  captured  by  such 
"  bait."  In  some  cases,  female  pupae  were  used  in  the  traps, 
and  gave  rather  surprising  results,  which  seem  to  indicate 
that  the  pupae  possess  in  some  degree  the  power  to  assemble 
male  moths,  as  twenty-one  female  pupae  attracted  seventy- 
two  males. 

The  following  is  a  summary  of  the  results  obtained : 
191  traps;  total  catch,  9,767  males;  average,  51.2  each; 
maximum  catch,  431  males ;  minimum  catch,  0 ;  maximum 
catch  by  a  single  female,  420 ;  minimum  catch  by  a  single 
female,  0. 

After  the  trapping  season  was  over,  the  localities  in  Med- 
ford,  where  the  greatest  number  of  males  was  captured, 
were  carefully  explored  and  the  egg-clusters  collected.  In 
the  latter  part  of  December  these  eggs  were  carefully  ex- 
amined and  their  fertility  determined,  with  the  following 
results  :  of  659  egg-clusters  examined,  16,  or  2.4  per  cent., 
proved  to  be  infertile.  As  a  check  on  the  work,  an  equal 
number  of  egg-clusters  taken  from  places  not  trapped  for 
males  were  collected  and  examined,  and  all  proved  fertile. 

OVIPOSITION. 

The  abdomen  of  the  female  is  so  heavy  before  depositing 
her  eggs  that  she  simply  clings  head  upward  to  the  trunk 
of  a  tree  or  other  object  on  which  she  happens  to  be  rest- 
ing (Plate  55)  ;  and  when  preparing  to  lay,  and  even  during 
the  process  of  depositing  the  egg-cluster,  she  drops  or  scat- 
ters more  or  less  eggs  accidentally.  A  small  hairy  area  is 
first  formed  by  rubbing  the  abdomen  over  the  surface,  thus 


364  THE   GYPSY  MOTH. 

depositing  a  small  quantity  of  hair,  which  is  caused  to  ad- 
here, probably  by  a  slight  discharge  of  fluids.  One  egg 
is  fastened  to  the  surface,  another  is  placed  beside  it  and 
others  on  each  side  of  these.  As  soon  as  the  foundation  is 
started,  other  eggs  are  laid  upon  it  and  the  mass  is  built 
along ;  that  part  of  the  cluster  next  to  the  surface  on  which 
the  moth  rests  is  always  kept  a  little  in  advance  of  the 
eggs  laid  on  top  of  it,  and  is  the  widest  part  of  the 
structure.  The  eggs  when  laid  are  covered  with  an  ad- 
hesive fluid,  which  not  only  causes  them  to  adhere  where 
they  have  been  placed  by  the  ovipositor,  but  also  causes 
the  abdominal  hair  of  the  female,  which  she  rubs  off  by  the 
continual  movement  of  the  abdominal  segments,  to  adhere 
to  them.  As  laying  progresses,  the  abdomen  shortens, 
and  the  hair  from  the  under  side  of  the  anterior  segments 
furnishes  the  covering  for  the  last-laid  eggs. 

The  term  layer  may  properly  be  applied  to  the  eggs  that 
are  deposited  on  the  surface  upon  which  the  moth  is  rest- 
ing, for  they  conform  to  that  surface,  however  smooth  or 
uneven  it  may  be,  but  those  outside  of  this  layer  are  packed 
in  very  irregularly.  In  nearly  every  case  where  the  eggs 
are  laid  upon  a  vertical  or  nearly  vertical  surface,  the  lay- 
ing is  done  from  below  upwards,  the  lower  eggs  being  the 
first  deposited,  while  the  upper  ones  are  the  last.  In  gen- 
eral, from  two  to  three  days  are  required  for  oviposition, 
but  the  time  is  subject  to  considerable  variation.  The 
greater  part  of  the  egg-cluster  is  usually  deposited  during 
the  first  twenty-four  hours.  In  one  case  a  large  female 
moth  which  began  laying  at  6  P.M.,  Aug.  6,  1895,  did  not 
complete  her  egg-cluster  until  11.30  A.M.,  August  16.  The 
female  does  not  usually  deposit  all  the  eggs  contained  in  the 
body.  In  the  case  of  the  female  mentioned  above,  there 
were  201  eggs  remaining  in  the  abdomen  of  the  moth,  while 
the  egg-mass  which  she  had  deposited  contained  794  eggs. 

EGGS    REMOVED   BY   DISSECTION    OF   FEMALE    MOTHS. 

The  female  moths  are  often  attacked  while  laying,  and 
mutilated  or  entirely  consumed  by  a  few  insectivorous  birds 
and  predaceous  insects.  Of  the  latter,  the  large  wood  ants, 
Camponotus  pennsylvanicus  (De  G.),  sometimes  kill  the  fe- 


PARTHENOGENESIS.  365 

male  moths,  gnaw  open  the  abdomen,  and,  after  removing 
the  egg-mass,  drag  it  to  their  nests.  With  the  discovery 
of  these  facts  the  question  naturally  arose,  whether  the 
eggs  thus  removed  from  fertilized  females  would  hatch  and 
thus  start  new  colonies  in  the  places  to  which  they  had  been 
carried.  To  settle  this  point,  during  the  summer  of  1895, 
studies  were  made  on  fifty  female  moths.  Some  of  these 
moths  were  taken  when  the  egg-cluster  was  about  one-third 
completed,  some  when  the  egg-cluster  was  one-half  com- 
pleted, some  when  two-thirds,  and  others  which  had  very 
nearly  completed  laying.  These  moths  were  dissected,  and 
all  of  the  eggs  still  remaining  in  the  abdomen  removed  and 
preserved  in  boxes.  Examinations  of  these  eggs,  made 
subsequently,  showed  that  none  of  them  were  fertile. 

A  part  of  the  egg-cluster  deposited  by  twenty-five  of 
these  moths  was  preserved,  all  of  which  proved  more  or 
less  fertile.  This  seems  to  demonstrate  that,  notwithstand- 
ing the  mating  of  the  moth,  the  eggs  are  not  fertilized  till 
during  the  process  of  laying. 

PARTHENOGENESIS  . 

Parthenogenesis,  or  reproduction  by  means  of  the  eggs  of 
unfertilized  females,  was  thought  to  offer  an  explanation  for 
the  existence  of  certain  peculiarly  situated  colonies  in  the 
infested  territory.  As  has  been  previously  stated,  cater- 
pillars are  sometimes  dropped  uninjured  by  the  birds  when 
they  are  carrying  them  away  to  feed  their  young ;  or  they 
may  spin  down  from  the  trees  upon  passing  teams  or  ani- 
mals, and  be  carried  to  greater  or  less  distances  and  then 
escape  to  suitable  food  plants,  where  they  can  feed  and 
pass  their  transformations.  If  a  single  caterpillar  should  be 
carried,  in  any  such  way,  to  a  distance  from  any  colony 
greater  than  males  could  be  attracted,  and  from  it  should 
emerge  a  female  moth,  she  would  doubtless  lay  her  eggs, 
and,  if  parthenogenesis  occurs  in  this  moth,  these  eggs 
might  hatch,  even  though  no  male  had  been  present  to  mate 
with  her. 

To  ascertain  whether  eggs  laid  by  unfertilized  females 
will  hatch,  in  July  and  August,  1893,  990  female  pupae  were 
put  in  small  pasteboard  boxes  and  kept  under  a  variety  of 


366  THE  GYPSY  MOTH. 

circumstances,  but  all  at  the  normal  out-door  temperature. 
Some  were  kept  covered  with  cheese  cloth,  others  with  the 
regular  box  covers,  and  still  others  were  kept  covered  a 
part  of  the  time  with  the  covers  and  the  rest  of  the  time 
with  cheese  cloth.  One  hundred  and  sixty  of  these  pupse 
were  from  larvae  raised  in  confinement,  while  the  rest  were 
collected  in  the  field.  Two  hundred  and  thirty-three  moths 
emerged  and  laid  their  eggs,  but  without  that  regularity 
that  characterizes  the  egg-clusters  of  fertilized  females. 
Most  of  the  females  laid  a  considerable  number  of  eggs, 
though  four  laid  no  eggs  but  deposited  some  of  their  hair ; 
one  laid  only  a  single  egg,  while  two  other  females  laid  four 
and  five  eggs  respectively.  The  boxes  containing  these  eggs 
were  kept  under  the  same  conditions  as  other  boxes  which 
contained  fertile  eggs,  which  hatched  at  the  usual  time  in 
the  spring ;  but  no  trace  of  embryonic  development  could 
be  discovered  within  them  during  the  fall,  and  they  were 
again  critically  examined  the  last  of  January,  1894,  when 
they  were  found  to  be  more  or  less  shrunken,  and  showed 
no  sign  of  an  embryo  within,  as  is  the  case  with  fertile  eggs. 
Early  in  the  spring  a  piece  of  glass  was  glued  over  the  top 
of  each  box,  so  that  the  young  caterpillars  could  not  escape, 
should  any  of  the  eggs  hatch.  They  were  daily  inspected 
till  after  the  time  when  they  should  have  hatched,  and  then 
once  a  week  till  July,  and  less  frequently  till  October,  1894, 
but  not  an  egg  hatched.  While  this  experiment  does  not 
prove  that  parthenogenesis  does  not  sometimes  occur  in  the 
gypsy  moth,  it  would  seem  to  indicate  that  it  is  probably 
of  rare  occurrence.  A  few  cases  have  been  reported  in 
Europe.  Carlier  states  that  he  has  seen  three  generations 
without  mating  having  taken  place,  but  the  last  genera- 
tion gave  only  males.  Siebold,  who  refers  to  this  case 
in  "Entomologische  Zeitung,  Stettin,"  Vol.  XXII,  page 
443,  expresses  some  doubt,  since  no  exact  account  of  events 
was  given.  Weijnbergh,  however,  has  given  a  very  com- 
plete account  of  breeding  this  species  from  unfertilized 
eggs  for  three  generations,  until,  at  last,  the  eggs  dried 
and  brought  his  observations  to  a  close.  Dohrn,  who 
reports  this  case  in  "Entomologische  Zeitung,  Stettin," 
Vol.  XXXII,  page  30,  expresses  the  opinion  that  the  dry- 


EGG-CLUSTERS  OF  UNFERTILIZED  FEMALES.   367 

ing  up  of  the  eggs  of  the  last  brood  was  not  due  to  their 
parthenogenetic  characteristics,  but  to  outside  influences, 
and  further  states  that  it  would  be  premature  to  limit  the 
vitality  of  the  products  of  parthenogenesis  to  two  genera- 
tions. It  is  a  matter  of  regret  that  Weijnbergh  did  not 
examine  the  eggs  each  fall,  and  see  whether  the  embryo 
had  formed ;  for,  had  this  been  found,  there  would  have 
been  greater  reason  to  have  supposed  that  the  eggs  had 
dried  up  because  of  outside  influences,  as  Dohrn  conjectured. 
Mr.  W.  J.  Pearce  of  Bath,  England,  reports  in  "  The  Ento- 
mologist," Vol.  XII,  page  229,  that  he  had  a  female  of  this 
moth,  which  had  not  mated,  lay  eggs  which  hatched  the 
following  year. 

EGG-CLUSTERS  or  UNFERTILIZED  FEMALES. 

The  egg-clusters  deposited  by  unfertilized  females,  in  the 
experiments  on  parthenogenesis,  in  1893,  were,  as  a  rule, 
irregular,  scattering  and  poorly  covered  with  hair.  As 
these  were  all  laid  in  boxes,  it  was  thought  that  it  might  be 
due,  in  part  at  least,  to  the  smoothness  of  the  box,  which 
did  not  allow  the  moth  as  good  a  foothold  for  oviposition 
as  is  afforded  by  the  surfaces  usually  selected  for  the  pur- 
pose, such  as  the  rough  bark  of  trees,  etc.  The  observa- 
tions of  the  field  inspectors  led  them  to  various  conclusions, 
some  contending  that  unfertilized  females  never  lay  the 
regular  egg-clusters  characteristic  of  the  fertilized  female, 
while  others  were  of  the  opposite  opinion.  Investigations 
were  made  during  the  summer  of  1895,  to  learn  whether  it 
is  possible  to  determine,  from  the  form  and  completeness  of 
an  egg-cluster,  whether  the  eggs  contained  in  it  are  fertile. 
August  2,  twenty-five  recently  emerged,  unfertilized  female 
moths  were  placed  in  a  cage,  made  by  tacking  cheese  cloth 
over  a  hoop,  which  projected  from  the  trunk  of  a  white  oak 
(  Quercus  alba) .  This  species  of  tree  was  selected  because 
the  bark  is  of  such  a  nature  as  to  give  the  moths  the  most 
favorable  opportunity  for  egg-laying.  At  the  end  of  two 
weeks,  all  the  moths  being  dead,  the  cage  was  opened  and 
six  very  imperfectly  formed  egg-clusters  were  found.  They 
were,  in  fact,  simply  small  patches  of  eggs,  with  but  little 
of  the  usual  covering  of  hair.  October  10,  the  eggs  were 


368 


THE  GYPSY  MOTH. 


shrivelled,  and  the  clusters  partly  washed  away  by  the  rains. 
From  these  as  well  as  other  observations  made  this  season 
it  seems  more  than  probable  that  a  female  gypsy  moth  that 
has  not  mated  does  not  make  a  perfect  egg-mass,  and  that 
an  experienced  observer  may  distinguish  in  most  cases  an 
egg-cluster  that  is  infertile  from  one  that  is  fertile. 

IN-AND-IN  BREEDING. 

A  cluster  of  eggs  laid  by  one  female  gypsy  moth  was 
placed  in  a  breeding  cage  in  the  spring  of  1893,  to  deter- 
mine whether  the  two  sexes  would  emerge  at  the  same  time, 
mate  and  lay  fertile  eggs.  This  was  for  the  purpose  of 
ascertaining  whether  it  would  be  possible  for  a  fertile 
female,  if  transported  to  a  new  region,  to  lay  eggs  capable 
of  establishing  a  new  colony ;  or,  if  a  single  cluster  of  eggs 
should  be  carried  outside  of  the  infested  region,  whether  a 
new  colony  would  result.  The  eggs  used  in  this  experi- 
ment commenced  hatching  May  5, 1893,  and  the  caterpillars 
were  fed  on  apple  leaves  till  they  reached  maturity,  when 
they  pupated.  The  moths  emerged  as  indicated  in  the  fol- 
lowing table :  — 


DATE. 

June 
». 

July 
1. 

July 
2. 

July 
8. 

July 
4. 

July 
6. 

July 
6. 

July 
7. 

July 

8. 

July 
9. 

July 
10. 

July 
12. 

Total. 

Male,   . 

3 

5 

8 

82 

13 

60 

76 

26 

2 

20 

19 

3 

267 

Female, 

-.. 

- 

2 

16 

15 

62 

69 

20 

4 

16 

- 

7 

211 

In  all  there  were  478  moths,  267  males  and  211  females, 
which  mated  as  readily  as  those  from  different  egg-clusters  ; 
and,  as  their  eggs  proved  fertile,  there  is  every  reason  to 
believe  that,  under  favorable  circumstances,  this  cluster  of 
eggs  could  have  established  a  colony  of  moths.  See  "  The 
Entomologist,"  Vol.  XIX,  page  281  (1886). 

INTERNAL  ANATOMY. 

The  following  description  of  the  internal  anatomy  of  the 
different  stages  of  the  gypsy  moth  was  prepared  by  Mr.  A. 
H.  Kirkland. 


PLATE  58. 


EXPLANATION  OF  PLATE  58. 


Drawn  by  A.  H.  KIRKLAND. 


1.  Internal  anatomy  of  larva  of  gypsy  moth    X    2  :    nc.,  nerve 

cord;  sg.,  silk  gland;  ce.,  oesophagus;  b.,  brain;  as., 
anterior  stomach;  dv.,  dorsal  vessel;  ps.,  posterior 
stomach;  ro.,  reproductive  organ;  mv.,  malpighian 
vessels;  i.,  intestine;  r.,  rectum. 

2.  Internal  anatomy  of  larva  about  to   pupate  X  2  :   as.,  ante- 

rior stomach;  ps.,  posterior  stomach;  dv.,  dorsal  ves- 
sel ;  ro.,  reproductive  organ. 

3.  Section    through    anal    segment    of  larva    about    to    pupate, 

showing  development  of  cremaster  in  anal  shield  X  4 : 
as.,  anal  shield;  c.,  cremaster;  r.,  rectum. 

4.  Section  through  head  of  larva  about  to  pupate,  showing  the 

development  of  the  antenna  cases  beneath  the  larval 
head  covering  X  4:  dv.,  dorsal  vessel;  ce.,  oesophagus; 
b.,  brain;  a.,  antenna  case. 

5.  Internal   anatomy  of  female   pupa  X  2:   dv.,  dorsal  vessel; 

ro.,  rudimentary  accessory  organs  of  reproductive  sys- 
tem ;  r.,  rectum. 

6.  Internal  anatomy  of  female  moth  X  2:   od.,  oviduct;   cp., 

copulatory  pouch;  nc.,  nerve  cord  and  ganglia;  s., 
atrophied  stomach;  b.,  brain;  dv.,  dorsal  vessel;  r., 
rectum ;  ag.,  accessory  glands  of  reproductive  system. 

7.  Right  silk  gland  of  full-grown  larva,  enlarged. 

8.  Posterior  tip  of  silk  gland,  greatly  enlarged. 

9.  Part  of  malpighian  vessel,  greatly  enlarged. 

10.     Part  of  dorsal  vessel  of  imago,  showing  aortic  arch. 


Drawn  by  R.  A.  COOLEY. 


11.  Micropyle  of  egg  with  surrounding  rosette,  greatly  enlarged. 

12.  A  part  of  the  same,  still  more  enlarged 


INTERNAL  ANATOMY.  369 

The  figures  of  the  internal  anatomy  were  made  from  dis- 
sections of  alcoholic  specimens  of  the  different  stages,  the 
work  being  performed  at  the  entomological  laboratory  of 
the  Massachusetts  Agricultural  College.  In  preparing  the 
material  for  dissection  the  insects  were  first  placed  for 
twenty-four  hours  in  fifty  per  cent,  alcohol,  then,  for  the 
same  period  of  time,  in  seventy-five  per  cent,  alcohol,  and 
then  kept  in  commercial  alcohol  until  needed  for  use.  The 
dissections  were  made  under  water,  by  using  a  small  wax- 
bottomed  dissecting  pan.  The  dissections  of  the  pupae  were 
not  wholly  satisfactory,  since  the  rapid  breaking  down  of 
the  larval  organs  and  the  correspondingly  rapid  development 
of  the  organs  of  the  imago  obscured  the  relations  of  the 
different  parts,  and  made  the  correct  interpretation  of  them 
a  difficult  task.  The  longitudinal  section  of  the  pupa,  as 
shown  in  Plate  58,  Fig.  5,  is  a  composite  figure,  made 
up  from  the  dissections  of  several  pupae  from  five  to  seven 
days  old. 

TJie  Alimentary  Canal  and  its  Appendages. 
From  the  medium  large  mouth  cavity  the  oesophagus 
(Plate  58,  Fig.  1,  oe)  leads  back  through  the  oesophageal 
collar  formed  by  a  division  of  the  double  commissure  which 
connects  the  brain  (b)  with  the  sub-oesophageal  ganglion  in 
the  first  thoracic  segment.  Here  it  expands  into  a  peculiar 
thin-walled  organ,  which,  from  its  position  and  size,  may  be 
called  the  anterior  stomach  (as).  This  anterior  stomach, 
which  is  practically  an  enlarged  continuation  of  the  oesoph- 
agus, is  distinctly  separated  from  the  posterior  stomach, 
stomach  proper,  by  a  well-defined  constriction  formed  by  a 
strong  sphincter  muscle,  possibly  valvular  in  function. 
The  anterior  stomach  fills  the  thoracic  and  a  part  of  the  first 
abdominal  segments.  A  marked  distinction  from  the  pos- 
terior stomach  is  the  fact  that  it  is  not  supplied  with  the 
prominent  annular  muscle  bands  which  are  characteristic  of 
the  latter  organ,  although  it  possesses  both  annular  and 
longitudinal  muscle  fibres.  In  the  larger  caterpillars  it  is 
usually  distended  by  a  dark,  viscid,  semi-fluid  mass,  con- 
taining the  recently  devoured  food,  and,  as  shown  by  micro- 
scopic examination,  numberless  bacteria.  The  posterior 


370  THE  GYPSY  MOTH. 

stomach  (ps)  extends  backward  from  the  anterior  stomach 
to  the  eleventh  segment  and  nearly  fills  the  body  cavity. 
The  contents  of  this  organ  are  of  a  more  solid  nature  than 
those  of  the  anterior  stomach.  In  the  eleventh  segment 
this  organ  tapers  abruptly  to  form  the  short  intestine  (i) , 
which  has  two  enlargements,  separated  from  each  other  by 
a  sharp  constriction.  Between  the  stomach  and  the  intes- 
tine, and  also  where  the  intestine  enters  the  rectum,  there 
is  a  well-marked  constriction.  In  the  last  body  segment 
the  intestine  expands  into  the  large  distended  rectum  (r) , 
which  completely  fills  the  cavity  and  discharges  at  the  anus 
beneath  the  anal  shield.  Six  narrow  longitudinal  muscles 
extend  the  entire  length  of  the  alimentary  canal.  These 
muscles  form  six  definite  depressions  on  the  intestine  and 
rectum,  and  give  to  the  excrement  of  the  larva  its  peculiar 
incised  appearance. 

The  malpighian  vessels  (Fig.  1 ,  mv)  consist  of  six  double 
convoluted  tubes  which  are  attached  to  the  walls  of  the  pos- 
terior stomach  ,and  discharge  into  the  intestine.  These  ves- 
sels are  simply  convoluted  tubes  (Fig.  9),  and  do  not  pos- 
sess the  bulbose  lateral  enlargements  found  in  many  other 
Lepidoptera.  They  are  composed  of  a  thin  outer  membrane 
and  an  inner  layer  of  thick-walled  nucleated  cells,  arranged 
around  a  central  lumen,  some  parts  of  which,  in  the  alco- 
holic specimens,  are  often  filled  with  a  yellow-brown  crys- 
talline mass  (urates) .  Fresh  malpighian  vessels  macerated 
in  water  give  quantities  of  minute  crystals.  I  have  been 
able  to  demonstrate  the  presence  of  uric  acid  in  these  ves- 
sels by  the  use  of  the  "  murexid  "  test. 

Small  white  granules  are  occasionally  found  deposited 
throughout  all  the  different  tissues  of  the  larva,  but,  owing 
to  their  extremely  small  size,  I  have  been  unable  to  collect 
a  sufficient  quantity  for  analysis.  In  similar  granules  re- 
moved from  the  tobacco  worm  (Protoparce  celeus)  I  have 
found  uric  acid,  as  shown  by  the  "  murexid"  test,  and 
phosphoric  acid,  as  demonstrated  by  the  reaction  with  am- 
monium molybdate. 

The  silk  glands,  two  in  number,  lie  along  the  lateral  walls 
of  the  body  cavity  of  the  larva.  Each  gland  consists  of  a 
small  thread-like  tube,  which  leads  forward  from  the  poste- 


INTEKNAL  ANATOMY.  371 

rior  part  of  the  body,  gradually  enlarging  in  the  seventh 
segment,  thence  extending  forward  to  the  fourth  segment, 
where  it  bends  on  itself  and  leads  backward  and  upward  to 
near  the  middle  of  the  eighth  segment.  Here  it  reaches  its 
maximum  diameter.  It  bends  downward  and  gradually 
tapers  again  to  a  thread-like  duct,  which  extends  forward, 
and,  after  a  more  or  less  irregular  course,  discharges  at  the 
spinneret  on  the  under  side  of  the  labium. 

In  the  full-grown  larva  (Fig.  1,  sg)  these  glands  are  dis- 
tended with  the  silk-forming  fluid  ;  in  those  which  have  spun 
their  cocoon  (Fig.  2)  they  have  contracted  to  less  than 
one-half  of  their  original  size.  One  of  these  glands  is 
shown  in  Fig.  7,  and  its  extreme  posterior  tip  in  Fig.  8. 

When  the  caterpillar  is  ready  to  pupate  (Fig.  2),  the 
alimentary  canal  is  emptied  of  its  contents,  the  anterior 
stomach  (as)  shrinks  to  less  than  one-half  of  the  diameter 
of  the  posterior  stomach  (ps),  the  latter  having  also 
shrunken  to  about  one-half  of  its  original  diameter.  The 
intestine  and  rectum  undergo  a  corresponding  diminution. 
In  the  pupal  stage  (Fig.  5)  the  anterior  stomach  grows  still 
narrower,  the  posterior  stomach  and  rectum  shorten,  while 
the  intestine,  although  less  than  one-fourth  of  the  diameter 
of  the  larva,  elongates  to  nearly  twice  its  original  length. 
In  the  imago  (Fig.  6)  the  digestive  system  is  atrophied,  the 
anterior  part  being  represented  by  a  slender  thread-like 
remnant  of  the  oesophagus  and  anterior  stomach,  while  the 
posterior  stomach  has  been  transformed  into  the  small 
shrunken  stomach  (Fig.  6),  at  the  hinder  end  of  which  may 
be  found  the  remains  of  the  malpighian  vessels.  A  slender 
intestinal  tube  connects  the  stomach  with  the  rectum  (r), 
which  lies  in  the  upper  posterior  part  of  the  abdominal 
cavity,  and  is  usually  filled  with  a  thick  cream  or  salmon 
colored  fluid. 

It  is  interesting  to  note  that  the  digestive  system  of  the 
male  imago  does  not  appear  to  have  undergone  so  marked 
a  degeneration  as  that  of  the  female.  The  stomach  is  much 
better  developed,  and  the  relation  of  the  different  parts  can 
be  more  clearly  demonstrated. 


372  THE  GYPSY  MOTH. 


Dorsal  Vessel  or  Heart. 

This  organ,  in  a  caterpillar,  is  a  simple  longitudinal  tube 
(Fig.  1 ,  dv) ,  lying  immediately  beneath  the  dorsal  line  and 
extending  the  whole  length  of  the  body.  It  is  closed  at  the 
posterior  end,  while  the  anterior  end  opens  at  the  base  of  the 
brain.  Bands  of  muscle  fibres,  placed  more  or  less  oblique- 
ly, appear  in  the  walls  of  the  organ,  while  it  is  supported  at 
the  sides  by  fan-shaped  muscles  (alae)  which  are  attached 
to  the  upper  body  walls. 

In  the  pupal  stage  (Fig.  5,  dv)  a  marked  bend  is  found 
near  the  anterior  end  of  the  dorsal  vessel,  while  faint  muscle 
fibres  can  be  traced,  extending  from  the  bend  to  the  dorsal 
wall  of  the  thorax. 

In  the  imago  (Fig.  6)  the  dorsal  vessel  (dv)  follows 
the  contour  of  the  upper  surface  of  the  abdomen,  bends 
abruptly  downward  at  the  junction  of  the  abdomen  and 
thorax,  enters  the  thoracic  cavity,  bends  obliquely  upward 
to  the  dorsal  wall,  where  it  is  firmly  attached  by  muscle 
fibres,  then  extends  downward  and  slightly  backward, 
thence  forward  to  the  head,  where  it  terminates  at  the  base 
of  the  brain.  I  have  been  unable  to  discover  any  aortal 
chamber,  such  as  was  found  by  Burgess  in  Anosiaplexippus, 
although  the  aortal  arch  (Fig.  10)  is  well  defined. 

Respiratory  System. 

This  system  is  not  figured  in  the  plates,  but  possesses  the 
general  features  common  to  Lepidoptera.  The  spiracles 
open  internally  by  short  tubes  which  communicate  with  two 
long  lateral  tracheae.  These  extend  the  whole  length  of  the 
body,  and  give  off  ramifications  to  all  the  organs.  Opposite 
the  spiracles  are  clusters  of  tracheae  of  medium  size,  which 
are  distributed  over  the  surface  of  the  alimentary  canal. 
The  tracheae  are  composed  of  an  outer  semi-transparent 
sheath,  made  up  of  large,  thin  cells,  the  nuclei  of  which  are 
readily  revealed  by  staining  with  haematoxylin.  "Within 
this  sheath  is  a  chitinous  tube,  bearing  on  its  inner  surface 
a  fine  spiral  ridge,  which  gives  the  tracheae  their  distinguish- 
ing characteristic. 


INTERNAL  ANATOMY.  373 

Nervous  System. 

This  consists  of  a  double  supra-cesophageal  ganglion  or 
brain  (Fig.  1,  b)  in  the  head,  an  cesophageal  collar,  a  sub- 
cesophageal  ganglion  and  a  row  of  ganglia  extending  along 
the  median  ventral  part  of  the  body  cavity.  The  ventral 
ganglia  are  connected  by  a  double  commissure  (nc).  The 
brain  gives  off  nerves  to  the  ocelli,  the  sub-cesophageal  gan- 
glion supplies  the  mouth  parts,  while  from  the  ventral  gan- 
glia nerves  are  distributed  to  the  feet,  prolegs  and  internal 
organs. 

In  the  caterpillar  there  are  eleven  ventral  ganglia,  includ- 
ing the  sub-o3sophageal.  The  posterior  one  is  by  far  the 
largest,  being  formed  by  a  fusion  of  two  ganglia.  During 
the  pupal  stage  (Fig.  5)  the  number  of  ganglia  is  reduced 
by  fusion.  In  the  imago  we  find  two  thoracic  and  four 
abdominal  ganglia,  which  are  connected  with  the  brain  by 
a  double  commissure. 

The  Fat  Body. 

In  its  fullest  development  this  body  forms  an  internal 
cylinder  of  fat,  which  surrounds  the  alimentary  canal  and 
lines  the  body  cavity  of  the  caterpillar.  It  is  represented 
by  the  dark  dotted  area  in  Plate  58,  Fig.  2.  It  is  liber- 
ally supplied  with  tracheae  and  is  most  prominent  in  well- 
fed,  full-grown  caterpillars.  In  the  pupal  stage  (Fig.  5)  the 
fat  body  diminishes  as  the  reproductive  system  develops,  the 
development  of  the  latter  taking  place  at  the  expense  of 
the  former.  One  fact,  which  seems  worthy  of  record  in 
this  connection,  is  that  almost  no  fat  can  be  found  in  the 
female  imago,  while  there  is  an  appreciable  quantity  pres- 
ent in  the  male.  Since  the  male  is  the  sex  that  flies,  this 
fat  may  be  necessary  to  furnish  the  energy  expended  in 
flight. 

Reproductive  System. 

This  system  is  represented  in  the  caterpillar  by  a  pair  of 
small  reddish-brown  organs  (Fig.  1,  ro),  which  lie  one  on 
each  side  of  the  dorsal  vessel  in  the  ninth  segment.  From 
these  organs  a  pair  of  thread-like  appendages  (ducts  ?)  lead 


374  THE  GYPSY  MOTH. 

backward  for  a  short  distance.  A  careful  sectioning  of  a 
single  reproductive  body  shows  it  to  be  composed  of  fila- 
»  ments,  which  are  coiled  upon  each  other,  forming  a  com- 
pact mass,  which  is  enclosed  in  the  external  envelope.  In 
the  mature  caterpillar,  and  even  in  those  of  the  fourth  molt, 
there  is  a  marked  difference  in  the  structure  of  the  repro- 
ductive organs,  seemingly  indicative  of  sexual  differentia- 
tion. One  form,  apparently  that  of  the  female,  is  made  up 
of  medium  long,  thick  tubes,  composed  of  an  outer  wall,  a 
thicker  inner  layer  and  a  central  lumen,  which  is  enlarged 
at  intervals,  and  contains  in  these  enlargements  large  cell- 
like  bodies  surrounded  by  many  smaller  cells  (nutritive 
cells?). 

That  which  is  apparently  the  male  form  is  made  up  of 
much  smaller  and  somewhat  longer  tubes  of  a  more  nearly 
even  diameter.  These  tubes  are  closely  coiled  on  each 
other  within  the  sac  formed  by  the  outer  envelope.  These 
organs  increase  in  size  as  the  insect  approaches  the  pupal 
stage.  Although  our  studies  on  the  reproductive  system 
in  the  pupa  are  not  yet  completed,  one  point  is  well  estab- 
lished :  the  development  of  the  reproductive  system  of  the 
future  imago  is  accompanied  by  a  corresponding  diminu- 
tion of  the  fat  body  with  which  the  newly  formed  pupae 
are  filled.  In  this  stage  the  accessory  organs  and  glands  of 
the  reproductive  system  are  first  recognizable  (Fig.  5,  ro). 
The  reproductive  organs  of  the  male  imago  (Plate  59, 
Fig.  1)  consist  of  a  single  button-shaped  testis  (t),  formed 
by  the  fusion  of  the  two  reproductive  bodies  of  the  cater- 
pillar ;  the  paired  seminal  vessels  (vs)  and  duct  with  the 
accessory  glands.  Four  enlargements  occur  on  each  of  the 
seminal  vessels,  two  near  the  testis  and  two  near  the  junc- 
tion of  the  two  vessels.  The  last  enlargement  has  a  blunt, 
lateral  projection,  which  receives  the  duct  from  the  acces- 
sory gland.  The  common  duct  formed  by  the  union  of  the 
two  seminal  vessels  tapers  for  a  considerable  part  of  its 
course,  then  enlarges  to  form  the  seminal  reservoir  proper 
(sr)  at  the  base  of  the  penis  (p),  into  which  it  discharges. 
Around  the  base  of  the  penis,  and  attached  to  the  lateral 
body  walls,  are  bands  of  muscle  fibre  (m),  which  evidently 
serve  to  exsert  the  organ.  The  whole  system  is  so  compli- 


EXPLANATION  OF  PLATE  59. 


Drawn  by  A.  H.  KIRKLAND. 


1.  Reproductive    system    of  male   imago,    greatly    enlarged:   t., 

testis;  ag.,  accessory  gland;  vs.,  vesicula  seminalis ; 
sr.,  seminal  reservoir;  m.,  muscle  at  base  of  penis; 
p.,  penis ;  co.,  Clasping  organs. 

2.  Reproductive   system  of  female   imago,  enlarged  :    rs.,  recep- 

tacle of  semen  or  copula tory  pouch;  od.,  oviduct; 
ag.,  accessory  glands;  oo.,  ovaries. 


PLATE  59. 


NATURAL  ENEMIES.  375 

cated  that  no  attempt  has  been  made  in  the  plate  to  repre- 
sent the  various  windings  of  the  vessels  and  glands  as  they 
occur  in  the  insect. 

The  female  reproductive  system  (Fig.  2,  also  Plate  58, 
Fig.  6)  consists  of  the  two  ovaries  (oo),  each  composed  of 
four  egg-bearing  tubes,  the  oviduct  (od)  formed  by  the 
union  of  the  ovarian  tubes,  the  accessory  glands  (ag),  and 
the  copulatory  pouch  or  receptacle  of  semen  (rs).  The 
ovarian  tubes  are  closely  coiled  upon  each  other,  and  form 
an  egg-mass  which  completely  fills  the  body  cavity.  On 
the  dorsal  surface  of  the  oviduct  is  the  point  of  union  with 
the  large  paired  and  small  single  accessory  glands.  These 
glands  probably  secrete  the  viscid  coating  of  the  eggs,  which 
enables  the  latter  to  adhere  in  masses  to  the  surface  on 
which  they  may  be  deposited.  Beneath  the  oviduct,  and 
connected  with  a  separate  external  opening,  is  the  copula- 
tory pouch  (Plate  58,  Fig.  6,  cp).  This  is  a  medium- 
sized  pear-shaped  organ,  and  connects  with  the  oviduct  by 
means  of  a  slender  tube. 

NATURAL  ENEMIES  OF  THE  GYPSY  MOTH. 

The  birds  which  play  so  very  important  a  part  in  destroy- 
ing the  gypsy  moth  have  been  fully  treated  of  in  Part  I  of 
this  work  by  my  colleague,  Mr.  Forbush,  and  we  pass  to 
the  consideration  of  the  other  natural  enemies  of  the  insect. 
Under  these  we  will  consider  the  animal  and  vegetable  para- 
sites, the  predaceous  insects  and  other  insectivorous  animals, 
except  the  birds. 

Hymenoptera. 

In  all  our  field  operations  we  have  endeavored,  from  the 
first,  to  learn  as  much  as  possible  about  our  native  parasites, 
and  particularly  to  what  extent  they  attack  the  gypsy  moth. 
For  this  purpose  we  have  paid  especial  attention  to  collect- 
ing the  different  species  found  to  be  parasitic  upon  this 
insect,  and  to  studying  their  habits.  The  Hymenopterous 
parasites  of  the  gypsy  moth  thus  far  found  are  as  follows  : 
Theronia  melanocephala  (Br.),  Pimpla peddlis  Cress.,  Pim- 
pla  tenuicornis  Cress.  (Plate  53,  Figs.  8,  8a),  Anisocyrta 
sp.,  Diglochis  omnivoi-us  (Walk.)  (Plate  53,  Figs.  10, 
lOa). 


376  THE   GYPSY  MOTH. 

The  first  two  and  perhaps  the  last  are  the  most  useful  in 
destroying  the  gypsy  moth,  and  probably  are  far  more 
successful  than  the  Dipterous  parasites,  since  the  latter  lay 
their  eggs  on  the  outside  of  the  caterpillars,  and  many  of 
them  are  thrown  off  on  the  molted  skin  before  they  hatch ; 
while  the  eggs  of  the  Hymenopterous  parasites  are  deposited 
in  the  tissues  beneath  the  skin. 

During  the  summer  of  1895,  Theronia  melanocephala 
(Plate  53,  Fig.  6)  was  the  most  abundant  of  the  Hymen- 
opterous parasites,  and  in  the  larger  colonies  could  be 
seen  on  warm  days  flying  about  from  tree  to  tree,  almost 
invariably  alighting  on  the  burlap  bands,  and  even  crawling 
under  them  in  its  search  for  pupae.  In  Lexington,  on  one 
occasion,  one  of  these  insects  was  seen  to  go  from  tree  to 
tree  until  it  had  examined  seven  burlaps.  After  searching 
the  burlaps,  the  trunk  of  the  tree  above  and  below  was 
inspected,  the  antennae  all  the  time  being  kept  in  constant 
motion.  It  has  been  reported  that  this  parasite  attacks 
the  caterpillar  when  about  to  pupate  ;  but  in  nearly  all  the 
cases  where  its  oviposition  was  observed  this  year,  some 
eight  or  ten,  the  insects  attacked  were  in  the  pupal  stage. 
The  point  of  attack  was  on  the  ventral  surface,  at  the 
lower  margin  of  the  wing-cases,  next  the  abdominal  seg- 
ments. Here  the  chitinous  integument  is  very  thin,  and 
offers  the  least  resistance  to  the  insertion  of  the  ovipositor. 
When  a  suitable  pupa  is  found,  the  parasite,  after  selecting 
the  point  for  attack,  curves  the  end  of  the  abdomen  beneath 
the  body  between  the  legs,  and  inserts  the  ovipositor  into  the 
pupa  by  a* succession  of  movements,  the  whole  operation 
requiring  about  a  minute  and  a  half.  When  disturbed  by 
the  writhing  of  the  pupa  or  otherwise,  the  parasite  with- 
draws her  ovipositor  and  later  stings  again.  Only  one 
parasite  has  been  reared  from  each  parasitized  gypsy  moth, 
and  therefore  we  may  infer  that  but  a  single  egg  is  deposited 
in  a  pupa.  Mr.  C.  E.  Bailey  captured  a  specimen  of  TJier- 
onia  melanocephala  in  the  act  of  stinging  a  gypsy  moth 
pupa  which  already  contained  a  Dipterous  maggot.  Un- 
fortunately, the  pupa  was  so  crushed  that  it  was  impossible 
to  ascertain  what  the  result  would  have  been. 

On  one  occasion  a  wood  pewee  was  seen  to  snap  up  one 


NATURAL  ENEMIES. 


377 


of  these  parasites,  while  apparently  in  search  of  pupae. 
There  is  no  doubt  that  our  birds  which  take  small  insects 
on  the  wing  also  destroy  many  Hymenopterous  and  Dipter- 
ous parasites. 

Pimpla  pedalis  (Plate  53,  Figs.  7,  7a)  was  obtained 
from  the  pupae  of  the  gypsy  moth  the  past  season,  as  well 
as  in  previous  seasons,  and  was  also  bred  in  great  numbers 
from  the  cocoons  of  the  tent  caterpillar  (  Clisiocampa  ameri- 
cana) .  From  about  two  quarts  of  the  cocoons  of  the  latter 
insect  only  twenty-five  moths  were  obtained,  the  rest  pro- 
ducing parasites,  most  of  which  were  Pimpla  pedalis,  though 
a  few  specimens  of  Theronia  melanocephala  were  also  ob- 
tained. Pimpla  pedalis  was  seen  ovipositing  in  the  cocoons 
of  the  tent  caterpillar ;  but  as  I  have  bred  this  parasite  from 
larvae  of  Tortrix  fumiferana  received  by  mail,  and  reared 
under  such  conditions  that  it  was  impossible  for  parasites  to 
approach  them,  I  am  led  to  believe  that  Pimpla  pedalis,  as 
well  as  Theronia  melanocephala,  oviposits  not  only  in  pupae 
but  also  in  caterpillars.  The  fact  that  these  parasites  breed 
in  the  tent  caterpillar  and  other  insects,  as  well  as  in  the 
gypsy  moth,  is  of  special  interest ;  for  the  tent  caterpillars 
pupate  about  four  weeks  earlier  than  the  gypsy  moth,  and  the 
parasites  emerge  from  them  just  in  time  to  attack  that  insect, 
so  that  this  succession  of  hosts  favors  the  multiplication  of 
the  parasites.  How  these  parasites  pass  the  winter  I  do  not 
know,  but  think  it  very  probable  that  they  hibernate  as 
imagoes.  Ichneumon  grandis  was  taken  in  January,  1895, 
hibernating  in  the  imago  stage,  in  a  stone  wall  at  Swamp- 
scott,  along  with  pupa  shells  of  the  gypsy  moth  and  cocoons 
of  Pyrrlmrctia  isabella. 

The  following  is  a  list  of  the  European  Hymenopterous 
parasites  of  the  gypsy  moth,  some  of  which,  however,  are 
known  to  be  hyperparasites  :  — 


Pteromalus   holiday  anus    Rtz. 

(hyper). 

Pteromalus pini  Hartig.  (hyper). 
Pteromalus    boucheanus     Rtz. 

(hyper). 

Eupelmus  bifasciatus  Giraud. 
Eurytoma  abrotani  Panz. 


Microgaster  calceatus  Hal. 
Microgaster  (?)  tenebrosus  Wesm. 
Microgaster  tibialis  Nees. 
Microgaster  (?)  liparidis  Rtz. 
Microgaster  pubescent  Rtz.  =  calcea- 
tus Hal. 
Microgaster  fulvipes. 


378  THE  GYPSY  MOTH. 


Apanteles  glomeratus  L. 
Apanteles  fulvipes  Hal. 
Apanteles  melanoscelus  Rtz. 
Apanteles  solitarius  Rtz. 
Pimplaflavicans  Rtz. 
Pimpla  instigator  Gr. 
Mesochorus pectoralis  Rtz. 
Mesochorus  gracilis  Brischke. 


Mesochorus  splendidulus  Gr. 
Mesochorus  confusus. 
Campoplex  conicus  Rtz. 
Campoplexdi/ormis  Gr.  =  Limneria. 
Pesomachus  hortensis  Gr.  (hyper). 
Hemiteles  fulvipes  Gr. 
Trogus  flavatorius  Pnz. 
Ichneumon  disparts  Poda. 


It  is  interesting  to  note  that  all  the  genera  included  in 
the  above  list  are  represented  by  species  in  this  country ; 
yet,  aside  from  the  genus  Pimpla,  no  members  of  the  dif- 
ferent genera  have  been  found  to  attack  the  gypsy  moth. 

Predaceous  Wasps  and  Hornets. 

The  following  species  of  wasps  and  hornets  have  been 
observed  feeding  upon  the  different  stages  of  the  gypsy 
moth:  Vespa  maculata  Linn.,  Vespa  consobrina  Sauss., 
Vespa  germanica  Fab.,  Polistes pallipes  St.  Farg. 

At  a  new  colony  of  gypsy  moths,  in  North  Saugus,  in  the 
early  part  of  August,  a  large  number  of  Vespa  maculata 
were  observed  flying  close  to  the  ground,  around  the  base 
of  the  trees  or  carefully  searching  the  trunks  up  and  down, 
sometimes  even  going  up  into  the  tops  of  the  trees.  They 
were  closely  watched,  and  a  maculata  was  seen  to  fly  after  a 
male  moth,  follow  its  zigzag  flight  as  it  attempted  to  escape, 
and  finally  capture  and  carry  it  to  a  small  branch.  The 
hornet  soon  dismembered  the  moth  and  began  feeding  upon 
the  abdomen. 

Two  other  hornets  of  the  same  species  were  seen  flying 
after  male  moths.  The  first  one  chased  a  moth  up  above 
the  tree  tops  and  then  off  to  one  side  and  out  of  sight. 
The  other  followed  a  moth  for  about  eight  rods  through  the 
woods,  and  then  caught  him,  but  flew  off  before  it  could  be 
taken  with  a  net. 

At  another  time  a  number  of  large  brown  wasps  (Polistes 
pallipes)  (Plate  53,  Fig.  5)  were  noticed  flying  about  the 
trees.  When  they  discovered  a  branch  on  which  caterpillars 
had  clustered  they  alighted,  and,  running  along  the  under 
side  of  the  branch  and  leaves,  each  wasp  located  its  prey, 
left  the  branch,  and,  flying  about  the  caterpillar,  finally 


NATURAL  ENEMIES.  379 

alighted  upon  its  back,  at  the  same  time  stinging  it  upon 
or  near  the  head,  usually  from  behind.  The  result  of  this 
was  to  completely  paralyze  the  caterpillar,  for  a  time  at 
least,  when  the  wasp  sucked  the  fluids  from  the  body  by 
cutting  holes  through  the  body  wall,  beginning  near  the 
head  and  working  toward  the  posterior  end.  In  some  cases 
the  wasp  nearly  cut  the  head  and  first  or  second  segment 
from  the  body,  and  not  unfrequently  they  were  seen  to  cut 
off  a  part  of  the  caterpillar  and  fly  away  with  it. 

The  work  of  the  wasps  was  not  confined  to  a  few  isolated 
cases,  but  they  were  busy  every  day  between  the  hours  of 
9  A.M.  and  3  P.M.,  killing  and  carrying  away  the  caterpillars. 

One  of  the  most  remarkable  observations  of  the  season  of 
1895  was  made  by  Mr.  C.  E.  Bailey,  a  most  careful  and  reli- 
able field  observer.  While  watching  the  birds  at  Wayte's 
Mount,  Maiden,  for  the  purpose  of  discovering  to  what  ex- 
tent the  different  species  of  birds  destroy  the  gypsy  moth, 
he  saw  a  large  insect  seizing  gypsy  moth  caterpillars  and 
flying  away  with  them.  Being  provided  with  a  net,  he  suc- 
ceeded in  capturing  this  insect  while  it  was  flying  away  with 
a  third-molt  gypsy  moth  caterpillar.  The  insect  proved 
to  be  the  American  saw-fly  (  Cimbex  americana) .  I  am  not 
aware  that  this  species  has  ever  before  been  discovered  to 
be  predaceous  in  its  habits,  but  its  mandibles  and  other 
mouth  parts  are  so  developed  that  one  can  well  believe  it 
capable  of  predaceous  propensities. 

Mr.  W.  L.  Tower  reported  that  on  July  17,  1894,  he  saw 
a  specimen  of  Tremex,  or  of  a  closely  allied  genus,  take  a 
full-grown  gypsy  moth  caterpillar  and  fly  away  with  it.  As 
the  insect  was  not  captured,  and  under  the  circumstances 
could  not  be  closely  identified,  we  should  not  have  con- 
sidered it  worth  while  to  mention  it  here  but  for  the  reason 
that  it  may  also  have  been  the  American  saw-fly,  and,  if  so, 
a  verification  of  the  predaceous  habits  of  that  insect.  An 
examination  of  the  mouth  parts  of  Tremex  columba  will  con- 
vince one  that  this  insect  is  not  predaceous,  and  therefore 
the  probabilities  are  increased  that  the  insect  seen  by  Mr. 
Tower  was  the  American  saw-fly. 


380  THE  GYPSY  MOTH. 

Ants  attacking  Female  Imagoes. 

The  following  field  observations  show  that  the  female 
imagoes,  while  laying,  are  often  attacked  and  killed  by 
black  ants. 

Aug.  11,  1894,  a  female,  trying  to  deposit  an  egg-cluster 
on  the  trunk  of  an  oak  tree,  was  attacked  at  10.20  A.M. 
by  a  large  black  ant,  which  seized  her  antennae  with  its 
mandibles.  The  ant  was  captured,  and  the  moth  resumed 
laying;  but  at  1.40  P.M.  was  found  in  a  hole  in  the  ground, 
with  a  number  of  ants  working  upon  her.  One  leg  was 
gone  and  two  more  nearly  severed  from  the  body.  At  2.40 
all  of  the  legs  and  both  antennae  were  missing,  and  the 
wings  nearly  destroyed.  At  4.40,  the  thorax  having  been 
severed  from  the  body  and  the  abdomen  opened  from  the 
anterior  end,  the  ants  commenced  to  carry  off  the  egg- 
masses. 

Another  female  moth,  while  crawling  in  the  grass,  was 
attacked  by  the  ants  at  11.40  A.M.,  which  seized  her  by  the 
ovipositor  and  dragged  her  some  distance.  At  2.40  P.M. 
the  ants,  still  at  work,  had  torn  the  head  from  the  body  and 
carried  it  up  into  the  tree,  and  soon  after  they  opened  the 
abdomen  and  greedily  devoured  the  ovarian  tubes.  A  third 
female,  just  beginning  to  lay,  was  seized  by  a  large  black 
ant,  which  dragged  her  to  the  ground,  where  nine  more  ants 
began  to  dissect  her.  The  antennae  and  legs  were  removed, 
the  abdomen  opened,  and  the  ants  soon  began  feeding  upon 
the  egg-masses. 

To  determine  whether  the  ants  will  eat  the  eggs,  the  fol- 
lowing investigations  were  made  :  Four  female  moths  were 
divested  of  their  heads  and  wings,  the  abdomens  opened  so 
as  to  expose  the  egg-masses,  and  then  placed  at  the  base  of 
four  tfees.  In  about  half  an  hour  two  of  the  moths  were 
visited  by  several  black  ants,  and  a  short  time  later  nine 
ants  were  working  upon  one  moth.  These  ants  feasted  for 
an  hour  or  more  upon  the  egg-masses,  with  their  mandibles 
closed  and  their  heads  thrust  down  among  the  eggs,  as  if 
sucking  up  the  body  fluids.  Then  they  began  to  sever  the 
thorax  from  the  abdomen  and  to  tear  off  small  clusters  of 
eggs,  from  three  to  seven  each,  and  carry  them  with  the 


PREDACEOUS   COLEOPTERA.  381 

other  parts  of  the  body  into  their  nests,  in  an  oak  tree,  two 
and  a  half  feet  from  the  ground.  When  the  last  piece  had 
been  removed,  the  large  ants  left  the  field  and  were  suc- 
ceeded by  a  smaller  species,  that  gathered  up  the  scattered 
eggs  and  minute  pieces  of  tissue  and  carried  them  off. 
Soon  the  large  black  ants  returned  to  another  moth,  and 
began  carrying  away  masses  of  eggs.  The  smaller  species 
worked  upon  the  same  insect,  but  were  not  able  to  make 
so  much  progress.  In  no  case  were  the  ants  seen  to  eat  a 
single  egg ;  they  only  devoured  the  body  tissues  and  fluids, 
particularly  the  ovarian  tubes  enclosing  the  eggs.  Two 
harvest  spiders  also  appeared  and  fed  upon  the  egg-masses. 

Specimens  of  these  ants  were  sent  to  Mr.  Theo.  Per- 
gande,  who  identified  them  as  Camponotus  pennsylvanicus 
De  G.  (Plate  53,  Fig.  9,  9a),  and  the  large  and  small 
workers  of  Formica  subsericea  Say. 

In  connection  with  the  attack  of  ants  upon  the  gypsy 
moth,  the  following  note  is  of  interest :  In  the  early  part 
of  the  work  of  trapping  the  male  moths,  in  1894,  attention 
was  called  to  the  fact  that  in  the  midst  of  the  most  densely 
infested  part  of  a  grove  there  was  a  single  hickory  tree  on 
which  no  egg-clusters,  caterpillars  or  any  trace  of  the  gypsy 
moth  had  been  found,  in  spite  of  the  fact  that  the  trees  and 
shrubs  almost  touching  it  on  every  side  were  all  found  to 
be  badly  infested.  The  tree  in  question  was  inhabited  by 
small  black  ants,  in  fact,  was  full  of  them,  and  to  these 
probably  owed  its  escape  from  the  ravages  of  the  gypsy 
moth,  while  other  trees  of  the  same  species,  not  inhabited 
by  ants,  were  infested.  The  larger  species  of  black  ants 
have  also  been  seen  feeding  on  dead  caterpillars  and  pupae 
of  the  gypsy  moth. 

Predaceous  Coleoptera. 

Several  species  of  beetles  have  for  some  time  been  known 
to  destroy  the  gypsy  moth.  On  the  20th  of  May,  1892, 
Mr.  C.  H.  Rowe  found  the  fiery  hunter  (  Calosoma  calidum} 
devouring  the  young  gypsy  moth  caterpillars  at  the  base  of 
an  oak  tree  in  Maiden.  The  beetle  was  captured,  and  sub- 
sequently liberated  in  a  breeding  cage  containing  thirty-six 
full-grown  caterpillars,  and  others  were  added  as  they  were 


382  THE  GYPSY  MOTH. 

needed.  In  five  days  ninety-three  caterpillars  were  de- 
stroyed, only  portions  of  the  larval  skins  remaining.  The 
beetle  was  fed  for  two  weeks  with  various  species  of  cater- 
pillars and  the  larvae  of  leaf-eating  beetles.  There  seemed 
to  be  no  choice  made  of  the  different  species  of  caterpillars 
supplied,  but  all  were  in  due  time  attacked  and  more  or  less 
eaten.  From  the  number  of  caterpillars  eaten  in  the  five 
days,  Mr.  Rowe  estimates  that  the  average  daily  consump- 
tion of  this  beetle  is  about  equal  to  six  full-grown  gypsy 
moth  caterpillars.  Mr.  Rowe  also  reports  the  larva?  of  two 
species  of  Harpalus  feeding  on  young  gypsy  moth  cater- 
pillars. 

For  the  purpose  of  ascertaining  more  fully  the  habits  of 
the  predaceous  beetles,  the  following  species  were  observed 
in  confinement,  in  the  insectary  at  Maiden,  during  the  sum- 
mer of  1895,  and  later  they  were  confined  and  fed  in  cages 
out  of  doors.  One  specimen  of  Calosoma  scrutator  was 
brought  in  June  28,  and  put  into  a  cage  with  ten  gypsy 
moth  caterpillars,  which  were  at  once  attacked  by  the  beetle. 
The  favorite  place  of  attack  seemed  to  be  the  middle  of  the 
body.  As  the  viscera  of  the  caterpillar  came  out  the  beetle 
chewed  away  steadily,  apparently  seeking  the  fatty  parts. 
In  two  days  fourteen  caterpillars  were  eaten.  At  the  end 
of  this  time  the  beetle  was  placed  in  a  cage  with  another 
individual  of  the  same  species.  July  1,  the  two  beetles 
killed  seven  gypsy  moth  caterpillars,  and  eleven  more  were 
put  in  the  cage.  The  next  day  ten  were  dead,  and  ten  more 
of  the  fourth  and  fifth  molt  were  put  in.  One  caterpillar 
pupated,  and  the  pupa  was  destroyed  by  the  beetles.  July 
3,  six  caterpillars  were  killed,  and  eight  more  of  the  fourth 
and  fifth  molt  were  put  in.  July  4,  one  of  the  beetles  died. 
The  remaining  beetle  killed  four  caterpillars  July  5,  but 
died  on  the  next  day,  after  killing  two  more  caterpillars. 
These  two  beetles  killed,  in  all,  thirty-six  gypsy  moth 
caterpillars. 

Another  individual  of  this  species  was  placed  in  a  cage 
July  2,  and  kept  supplied  with  gypsy  moth  caterpillars. 
July  18,  another  beetle  of  the  same  species  was  placed  in  the 
cage  and  supplied  with  food.  The  first  beetle,  during  the 


PREDACEOUS   COLEOPTERA.  383 

fifteen  days  before  the  second  was  put  in,  destroyed  thirty- 
one  caterpillars  and  three  pupae ;  and,  after  the  other  beetle 
was  put  in  with  it,  the  two  destroyed  fifty  gypsy  moth 
caterpillars  and  one  Sphinx  drupiferarum  caterpillar  before 
July  24,  when  the  first  beetle  died.  The  remaining  beetle 
destroyed  four  gypsy  moth  caterpillars,  one  sphinx  cater- 
pillar and  one  male  gypsy  moth  between  July  24  and  July 
30.  Another  Calosoma  scrutator  was  then  put  into  the  cage, 
and  August  5,  when  they  were  placed  out  of  doors,  they  had 
killed  eight  caterpillars,  three  pupae  and  two  female  moths. 

Two  specimens  of  Calosoma  frigidum  (Plate  53,  Fig. 
1) ,  male  and  female,  were  put  into  a  cage  together  at  the  in- 
sectary,  June  28,  and  supplied  with  gypsy  moth  caterpillars. 
This  species  is  much  smaller  and  more  active  than  C.  scru- 
tator. They  are  not  so  clumsy,  but  are  able  to  seize  the 
caterpillars  and  destroy  them  while  on  a  vertical  surface,  as 
on  the  trunk  of  a  tree.  July  27,  one  of  these  beetles  died, 
and  the  other  was  removed  to  be  used  by  the  artist.  Dur- 
ing this  time  they  killed  ninety-two  gypsy  moth  caterpillars, 
three  pupae  and  one  female  moth. 

Three  other  individuals  of  this  species  were  put  into  a 
cage  in  the  insectary,  July  21,  and  supplied  with  gypsy 
moth  caterpillars.  One  of  the  beetles  died  the  second  day, 
and  on  August  5  the  other  two  were  placed  in  an  outside 
cage.  During  the  fifteen  days  that  these  beetles  were  fed 
in  the  insectary  they  killed  thirty-nine  gypsy  moth  cater- 
pillars, two  pupae,  two  sphinx  caterpillars  and  one  cut- 
worm. 

Calosoma  calidum.  —  Three  specimens  of  this  beetle  were 
placed  in  a  cage  July  12,  and  supplied  with  gypsy  moth 
Caterpillars.  July  19,  twenty-three  caterpillars  had  been 
killed,  and  another  beetle  was  put  into  the  cage.  July  27, 
one  of  the  beetles  died,  the  four  having  killed  thirty-four  cat- 
erpillars and  one  pupa  since  July  19.  Fifteen  gypsy  moth 
caterpillars,  four  pupse,  eight  cut-worms  and  two  Sphinx 
drupiferarum  caterpillars  were  killed  between  July  27  and 
August  5. 

One  specimen  of  Carabus  serratus  was  supplied  with 
gypsy  moth  caterpillars,  and  killed  five  before  it  died. 


384  THE   GYPSY  MOTH. 

Platynus  limbatus  was  also  found  feeding  on  pupse  in  the 
field,  but  it  would  not  feed  upon  them  in  confinement. 

For  the  purpose  of  keeping  and  feeding  some  of  our  pre- 
daceous  beetles,  under  as  natural  conditions  as  possible, 
Mr.  Kirkland  very  ingeniously  arranged  a  number  of  cages 
(Plate  60) ,  and  attached  them  to  the  trunks  of  trees  in  the 
woodland  near  the  insectary.  These  cages  were  of  wire 
netting,  bent  into  a  nearly  cylindrical  form.  The  edges 
were  fastened  to  the  two  sides  of  the  tree  trunk,  the  lower 
end  extending  down  into  the  ground  and  the  upper  end 
covered  by  a  piece  of  cloth,  one  side  of  which  was  secured 
to  the  tree,  the  other  covering  the  top  of  the  wire  screen 
cage,  and  held  in  place  by  a  rubber  strap,  the  ends  of  which 
were  fastened  to  the  trunk  of  the  tree.  This  rubber  band 
could  easily  be  removed  from  the  top  of  the  cage  and  the 
cloth  lifted  sufficiently  to  give  free  access  to  the  interior. 
A  few  small  stones  and  some  moss  were  so  arranged  on  the 
ground,  at  the  bottom  of  the  cage,  as  to  furnish  hiding- 
places  for  the  beetles.  Each  cage  had  a  tag  attached  to  it, 
on  which  was  the  number  and  other  necessary  data. 

Two  specimens  of  Calosoma  scrutator  were  placed  in  cage 
No.  1,  August  9,  and  supplied  with  gypsy  moth  caterpillars. 
August  20,  fourteen  caterpillars  had  been  killed. 

Five  specimens  of  Calosoma  frigidum  and  one  of  Calo- 
soma calidum  were  put  into  cage  No.  2,  August  9,  and 
supplied  with  caterpillars.  One  specimen  of  C.  frigidum 
died  August  13,  and  August  20,  twenty-five  caterpillars  had 
been  killed  by  these  beetles. 

Ten  specimens  of  Harpalus  caliginosus  were  put  into  cage 
No.  3,  August  9,  and  supplied  with  caterpillars,  and  August 
20,  twenty- two  of  these  caterpillars  had  been  destroyed  by 
the  beetles. 

Ten  specimens  of  Harpalus  pennsylvanicus  were  placed 
in  cage  No.  4,  August  9,  and  furnished  with  caterpillars ; 
August  20,  twenty-three  caterpillars  had  been  killed  by  the 
beetles. 

During  the  summer  of  1891,  Mr.  E.  P.  Felt  obtained  a 
specimen  of  Dermestes  lardarius  from  a  mass  of  gypsy  moth 
pupae. 


PARASITIC   DIPTERA.  385 

Several  Coleopterous  larvae  have  been  found  feeding  upon 
the  egg-clusters  of  the  gypsy  moth,  but  we  have  been  unable 
to  obtain  the  imagoes  from  them.  During  the  past  year 
Mr.  C.  H.  Howe  succeeded  in  rearing  a  specimen  of  Ptinus 
bninneus  from  a  gypsy  moth  egg-cluster. 

The  following  species  of  predaceous  beetles  are  said  to 
attack  the  gypsy  moth  in  Europe  :  — 

Calosoma  sycophanta  (L.)  (larva). 
Tiresias  serra  (Fab.)  (eggs). 
Dermestes  ater  (Panz.)  (eggs  and  pupae). 
Dermestes  lardarius  (L.)  (eggs  and  pupse). 

Diptera. 

In  June,  1891,  while  on  a  visit  to  the  territory  infested 
by  the  gypsy  moth,  my  attention  was  first  called  to  the  fact 
that  flies  were  depositing  their  eggs  on  the  caterpillars  ;  and 
.since  that  time  the  field  workers  have  reported  these  para- 
sitic flies  in  no  less  than  ten  towns,  showing  that  they 
probably  occur  throughout  the  entire  infested  region.  The 
number  of  these  eggs  on  a  single  caterpillar  was  reported 
by  twelve  different  inspectors  who  observed  them,  as  vary- 
ing from  one  to  twenty,  though  some  state  that  they  have 
seen  the  caterpillars  "  nearly  covered,"  and  others  "  eggs  in 
great  numbers  on  them."  Directions  were  then  given  to 
collect  and  rear  the  parasitized  caterpillars  till  these  para- 
sites should  emerge.  It  was  found  that  many  of  the  cater- 
pillars molted  their  skins  before  the  eggs  of  the  parasites 
hatched,  and  therefore  comparatively  few  of  them  were  able 
to  make  their  way  into  their  insect  hosts  and  destroy  them. 
If  the  caterpillars  had  not  molted  before  the  eggs  of  the 
parasites  hatched,  their  destruction  would  have  been  vastly 
greater.  During  the  summer  of  1893,  Mr.  Reid  collected  a 
number  of  caterpillars  on  which  the  eggs  of  the  parasites 
had  been  laid.  Two  hundred  and  thirty-five  of  these  cater- 
pillars, having  from  one  to  thirty-three  eggs  on  them,  were 
fed  in  cages  until  they  changed  to  pupse;  and  from  these 
two  hundred  and  twenty-six  moths  emerged,  but  only  four 
Dipterous  parasites  were  secured  from  this  entire  number. 
The  caterpillar  which  had  thirty-three  parasite  eggs  on  it 


386  THE   GYPSY   MOTH. 

when  brought  in  molted  before  these  eggs  hatched,  passed 
all  its  transformations,  and  the  moth  emerged  from  it  in 
good  condition. 

In  July,  1895,  a  careful  examination  was  made  to  deter- 
mine the  proportion  of  caterpillars  in  the  field  that  had  the 
eggs  of  the  Dipterous  parasites  attached  to  them.  July  3, 
five  trees  were  examined  in  Dorchester,  and  2,200  cater- 
pillars were  found,  500  of  which  had  the  eggs  of  parasites 
on  them.  July  8,  six  trees  were  examined  in  Medford,  and 
1,847  caterpillars  found,  397  of  which  bore  parasite  eggs. 
The  total  number  of  caterpillars  examined  was  5,547,  of 
which  1,597,  or  nearly  29  per  cent.,  had  the  eggs  of  Dip- 
terous parasites  attached  to  some  part  of  the  body. 

Several  Dipterous  parasites  were  bred,  during  the  summer 
of  1895,  from  infested  pupae,  the  majority  of  which  pro- 
duced only  one  parasitic  fly,  while  a  few  produced  two. 
Many  parasitized  pupae  contain  maggots  which  have  not  yet 
pupated.  The  vitality  of  these  Dipterous  parasitic  larvae  is 
very  remarkable.  One  of  them  was  placed  in  a  twenty  per 
cent,  solution  of  formol  at  night,  August  15,  and  twenty- 
four  hours  later  it  was  found  swimming  around,  apparently 
uninjured.  The  larva  was  at  once  removed  from  its  formol 
"  bath,"  and  was  still  living  October  1,  but  had  not  pupated. 
In  several  cases  where  two  larvae  were  found  in  a  small  pupa 
of  the  gypsy  moth,  and  there  seemed  an  insufficient  amount 
of  food  for  them,  a  large  female  pupa  was  cut  open  and  a 
parasite  larva  placed  on  the  cut  end  of  each  half.  They  at 
once  burrowed  into  the  tissues  and  fed  there  several  days. 
One  larva  ate  the  substance  of  six  female  pupae  in  this  way 
before  reaching  its  full  growth. 

Fifty  gypsy  moth  caterpillars,  having  eggs  of  a  Dipterous 
parasite  on  them,  were  collected  in  Dorchester,  June  21, 
1895,  and  carefully  bred  in  separate  boxes.  The  eggs  were 
deposited  without  regularity  on  nearly  every  part  of  the 
body.  Forty-three  of  these  caterpillars  passed  their  trans- 
formations, producing  perfect  moths,  six  males  and  thirty- 
seven  females ;  while  seven  died,  but  not  because  of  the 
parasites,  for  the  caterpillars  had  all  molted  before  the  eggs 
of  the  parasite  had  hatched.  Two  hundred  and  fifty-two 


PARASITIC   DIPTERA.  387 

other  caterpillars  taken  in  the  field,  and  bearing  Dipterous 
eggs,  were  fed  and  carried  through  their  transformations 
with  the  same  result  as  in  the  case  cited  above. 

All  the  Dipterous  parasites  bred  from  the  gypsy  moth, 
and  also  those  collected  in  1891,  were  sent  to  Dr.  S.  W. 
Williston  for  determination.  They  were  determined  by 
him  as  follows  :  — 

Exorista,  two  species ;  Phorocera,  four  species.  These 
are  true  parasites. 

Gaurax  anchora  Loew,  whose  larvae  had  been  observed 
by  Osten  Sacken  in  multitudes  upon  the  pupae  enclosed  in 
the  cocoons  of  the  Cecropia  moth ;  Phora  scalaris  Loew ; 
Phora  incisuralis  Loew,  var.  The  last  three  species  are 
regarded  by  Dr.  Williston  as  accidental  parasites  entering 
the  pupae  of  the  gypsy  moths  while  the  flies  are  in  the  larval 
state,  and  then  feeding  in  and  destroying  the  moths. 

Sarcophaga,  two  species.  Schiner  expresses  very  grave 
doubts  whether  the  species  of  Sarcophaga  ever  feed  on  any- 
thing but  dead  animal  matter,  while  Brauer  states  that  their 
larvae  are  sometimes  parasitic. 

Cyrtoneura  stabulans  Fall.  According  to  Hartig  and 
Brerni,  the  larva  of  this  species  is  sometimes  found  in  the 
caterpillars  of  certain  Bombycid  moths. 

In  1894,  I  sent  another  lot  of  Diptera  bred  from  the  gypsy 
moth  to  Dr.  Williston  for  determination,  and  in  reply  he 
wrote  as  follows  :  "I  send  you  herewith  the  manuscript  on 
the  Diptera  sent  me,  except  a  portion  of  that  formerly  sent 
to  you,  the  specimens  of  which  have  got  mislaid  or  rather 
lost  in  the  general  collections,  and  have  not  yet  been  found. 
There  were  several  specimens,  how  many  I  do  not  know, 
but  not  including  the  Tachinids  which  I  had  separated  out." 
Should  the  above-mentioned  species  be  found,  there  may 
prove  to  be  something  of  interest  to  add  to  our  list.  Dr. 
Williston  kindly  sent  the  following  descriptions  for  publi- 
cation in  this  report  :  — 

Achcetoneura  fernaldi  n.  sp.  (Plate  53,  Fig.  11,  a-e.) 
Male.  —  Frontal  stripe  deep  brown,  a  little  narrower  than 
the  sides  of  the  front;  sides  light  golden  yellow,  reaching 
a  little  way  on  the  sides  of  the  face.  At  each  angle  of  the 


388  THE   GYPSY  MOTH. 

eye  there  is  a  stout  bristle  curved  backward ;  on  either  side 
of  the  frontal  stripe  a  single  row  of  bristles,  of  which  the 
two  uppermost  are  stronger  than  those  before  them,  and  are 
curved  backward.  The  frontal  row  extends  down  on  the  sides 
of  the  face  for  a  short  distance  beyond  the  base  of  the  an- 
tennae and  to  nearly  opposite  the  uppermost  bristle  of  the 
facial  row ;  the  proclinate  ocellar  bristles  moderately  strong. 
Antennae  wholly  black,  the  third  joint  but  little  more  than 
three  times  the  length  of  the  second  joint.  Face  satiny 
white  ;  vibrissal  bristles  situated  a  little  distance  above  the 
oral  margin  ;  above  them  is  a  row  of  not  very  strong  bristles 
extending  about  midway  to  the  root  of  the  antennae.  Sides 
of  the  face  wholly  bare,  except  for  the  previously  mentioned 
bristles.  Cheeks  covered  with  short,  black,  bristly  hairs, 
their  length  equal  to  about  half  that  of  the  eyes.  Eyes 
wholly  bare.  Palpi  yellowish.  Mesonotum  shining  blue 
black,  with  inconspicuous  stripes.  Scutellum  broadly  red- 
dish on  the  apex,  the  apical  pair  of  bristles  small  and  decus- 
sate. Abdomen  shining  blue  black,  with  a  broad,  variable, 
white  pollinose,  basal  band  on  the  segments;  first  and 
second  segments  each  with  a  pair  of  marginal  bristles; 
third  segment  with  a  posterior  row ;  the  general  covering 
of  the  abdomen  is  composed  of  rather  stout  bristly  hairs, 
which  are  more  abundant,  longer  and  intermixed  with  finer 
hairs  distally.  Legs  wholly  black,  the  front  femora  whitish 
pollinose  behind ;  pulvilli  much  elongated ;  the  claws  elon- 
gate and  slender.  Wings  grayish  hyaline  ;  third  vein  with 
a  few  short  bristles  at  the  very  beginning ;  angle  of  the 
fourth  vein  without  a  stump,  though  with  a  fold  appearing 
somewhat  like  one. 

Female.  — Differs  from  the  male  in  the  front  being  wider, 
in  the  presence  of  two  proclinate  orbital  bristles  on  each 
side,  in  the  abdomen  being  less  hirsute  and  in  the  short 
claws  and  pulvilli.  Length  of  male,  10  mm.  ;  of  female, 
12  mm. 

Twenty-five  specimens  from  Professor  Fernald,  labelled 
as  follows :  '  *  From  larvae  which  died  in  parasitic  cage 
Aug.  27  (male),  28  (male  and  female),  29  (male),  1893, 
laboratory  Gypsy  Moth  Department,  Maiden."  "  Emerged 


PAKASITIC  DIPTERA.  389 

from  pupa  of  P.  dispar  Aug.  22,  1893  n  (female)  ;  and 
"Emerged  from  gypsy  moth  pupae  Aug.  24  (male),  27 
(female),  29  (female),  1891;  Sept.  2  (female),  1891." 

I  have  compared  these  specimens  with  a  female  type  of 
A..  (Masicera)  frenchi  Williston,  with  which  the  species  is 
closely  allied,  and  find  the  following  differences  :  The  facial 
bristles  ascend  higher  in  A.  frenchi,  reaching  two-thirds  or 
more  of  the  distance  to  the  root  of  the  antennae,  while  in 
A.  fernaldi  they  do  not  go  more  than  half  way,  and  some- 
times even  less  than  that.  The  bristles  of  the  front  do  not 
descend  so  far  as  in  A.  frenchi.  But  the  chief  difference, 
and  one  by  which  the  species  will  be  readily  recognized,  is 
the  relatively  much  shorter  third  joint  of  the  antennae  in  the 
present  species.  In  A.  frenchi  it  is  fully  five  times  the 
length  of  the  second.  The  marginal  bristles  of  the  abdo- 
men seem  to  be  stronger  in  A.  frenchi.  In  the  type  female 
compared  there  are  none  on  the  first  segment,  but  I  suspect 
that  the  species  has  them  normally. 

From  Achcetoneura  (Masicera)  sphingivoraTowns., Trans. 
Am.  Ent.  Soc.,  Vol.  XIX,  page  286,  the  length  of  the 
antennae  and  the  red  sides  of  the  abdomen  are  sufficient 
to  distinguish.  From  A.  (Masicero)  eufitchim  Towns,  the 
differences  are  also  evident. 

Sarcophaga,  sp.  Female.  —  Sides  of  the  front  and  face 
wholly  silvery  white  ;  median  frontal  stripe  black.  Antennae 
black,  third  joint  between  three  and  four  times  the  length 
of  the  second  joint.  Abdomen  black,  silvery  white,  mar- 
morate ;  fourth  segment  wholly  black.  Legs  black,  the 
hind  tibiae  not  ciliate.  Palpi  black.  Length,  12  mm. 

One  specimen,  labelled  "From  parasitic  material,  Aug. 
1,  1893,  Gypsy  Moth  Department,  Maiden."  The  single 
specimen  is  not  in  the  best  state  of  preservation,  and  it  is 
difficult,  if  not  impossible,  to  either  identify  it  with  any 
previously  described  species  or  to  give  a  description  which 
will  enable  the  species  to  be  again  determined  with  cer- 
tainty. The  diagnosis  given  above  wil  serve  to  exclude  all 
but  nearly  related  species. 

Oyrtoneura  stabulans. — Musca  stabulans  Fallen.  Mei- 
gen,  Schiner  (Cyrtoneura},  etc.  Europe,  New  Zealand, 
Xorth  America. 


390  THE   GYPSY  MOTH. 

Female.  —  Front  a  little  less  than  one-third  of  the  width 
of  the  head,  gray  pollinose  on  the  sides,  the  median  stripe 
deep  reddish  brown  or  black,  broader  than  the  sides,  nar- 
rowed below ;  a  pair  of  proclinate  ocellar  bristles  pres- 
ent; the  lateral  row  of  bristles  has  an  outward  curvature. 
Second  joint  of  the  antenna  reddish;  in  front  somewhat 
blackish,  and  with  erect  bristles ;  third  joint  black,  about 
three  times  the  length  of  the  second;  arista  thickened  at 
the  base,  plumose.  Sides  of  the  face  narrow,  bare.  Cheeks 
in  width  about  equal  to  the  length  of  the  third  joint  of  the 
antennae,  with  a  row  of  bristles  on  the  inferior  margin 
reaching  to  the  moderately  stout  vibrissae  a  little  above  the 
oral  margin ;  bare  on  the  upper  part,  and  with  short  bristly 
hairs  below.  Sides  of  the  face  and  the  upper  part  of  the 
cheeks  reddish  in  ground  color,  covered  with  silvery  pubes- 
cence. Mesonotum  gray  pollinose,  variable,  with  four  nar- 
row, shining  black  stripes,  the  lateral  ones  interrupted. 
Scutellum  broadly  reddish  at  the  apex ;  apical  bristles  long, 
decussate.  Abdomen  uniformly  covered  with  gray  pol- 
len, moderately  variable  in  diiferent  reflections,  the  ground 
color  everywhere  shining  black.  Legs  yellow ;  the  front 
femora  in  large  part  and  the  base  of  the  middle  femora 
black ;  all  the  tarsi  blackish.  Wings  grayish  hyaline  ;  first 
posterior  cell  only  a  little  narrowed  at  the  tip  ;  penultimate 
section  of  the  fourth  vein  shorter  than  the  antepenultimate 
section.  Length,  6-7  mm. 

Three  specimens,  labelled  "Emerged  from  gypsy  moth 
pupre,  Aug.  20—21  and  25,  1891."  This  species  is  the  one 
which  I  have  commonly  identified  as  C.  stabulans  Fall.,  but 
I  have  never  compared  it  directly  with  European  specimens. 
According  to  Schiner,  it  has  been  bred  from  Bombyx  pyri 
and  Lophyrus,  and  also  from  various  species  of  Boletus. 

Nlachiptera  dispar  n.  sp.  (Plate  53,  Figs.  12  and  12a.) 
Female.  —  Head  yellow,  a  minute  spot  at  the  ocelli  and  the 
arista  black.  Thorax  light  yellow ;  a  narrow  median  stripe 
extending  from  the  front  margin  of  the  mesonotum  to  the 
tip  of  the  scutellum;  a  small  oblique  spot  on  each  side, 
contiguous  with  the  front  end  of  the  stripe,  and  the  disk  of 
the  mesonotum,  black.  Abdomen  yellow  ;  second  segment, 


PARASITIC   DIPTERA.  391 

except  a  broad  triangle  whose  apex  reaches  the  hind  mar- 
gin, and  all  of  the  following  segments,  black.  Legs  light 
yellow;  the  front  tibiee  and  tarsi  brown,  the  other  tarsi 
brownish.  Wings  cinereous  hyaline.  Length,  2  mm. 

Two  specimens,  labelled  "Emerged  from  gypsy  moth 
pupae,  Aug.  21,  1891."  The  arista  has  been  broken  away 
in  both  specimens,  save  the  basal  part ;  this  part,  however, 
is  so  thickened  and  pubescent  that  I  believe  that  I  am  not 
in  error  in  referring  the  species  to  Elachiptera  (  Crassiseta) , 
where  it  finds  its  nearest  ally  in  E.  eunota  Loew. 

Phora  setacea  Aldrich,  Can.  Ent.,  Vol.  24,  page  144, 
Brookings,  South  Dakota  (reared  from  Cimbex  americana). 

Notwithstanding  the  difference  of  locality  and  habits,  I 
believe  that  the  specimens  bred  frpm  the  gypsy  moth  par- 
asitic material  and  sent  to  me  by  Professor  Fernald  are  of 
the  same  species  as  those  described  by  Professor  Aldrich. 
I  have  only  males,  and  it  is  possible  that  the  females  may 
show  some  discrepancies.  The  specimens  differ  from  the 
description  only  in  the  male  genitalia,  which  do  not  have 
the  projecting  abdominal  segment  as  described,  and  in  the 
first  weak  vein  of  the  wings,  which  is  distinctly  curved  and 
not  "  almost  straight."  The  species  will  be  best  recognized 
by  the  arrangement  of  the  lowermost  frontal  bristles,  for 
the  position  of  which  the  reader  is  referred  to  the  figure  and 
description  given  by  Aldrich.  Otherwise  the  species  may 
be  briefly  described  as  follows  :  — 

Male.  —  Head  black,  antennae  fuscous  ;  palpi  yellow,  with 
black  bristles  ;  proboscis  yellow.  Thorax  black.  Abdomen 
black  ;  halteres  light  yellow.  Front  and  middle  legs  yellow, 
the  hind  ones  more  brownish.  One  spur  at  the  tip  of  the 
tibia?,  save  of  the  front  pair,  where  there  are  none.  Wings 
hyaline ;  second  heavy  vein  (third  longitudinal)  furcate ; 
bristles  on  costal  border  long.  Length,  1.5  mm. 

It  is  probably  true  that  the  species  of  PJiora  are  not  truly 
parasitic,  but  live  in  any  dead  or  decayed  material  that 
comes  in  their  way ;  still,  it  is  not  certain  but  that  they  may 
attack  the  living  insect. 

The  following  list  of  the  European  Dipterous  parasites 
of  the  gypsy  moth  has  been  compiled  from  various  sources. 


392 


THE   GYPSY   MOTH. 


Many  of  the  names  are  taken  from  a  list  furnished  me  by 
Dr.  S.  W.  AVilliston  :  — 


Eiorista  Incornm  Meig. 

Exorista     (Myxexorista)     libatrix 

Pan  7.. 

Exorista  erythrostoma  Hrtg. 
Parexorista  sussorans  Kond. 
Meigenia  bisignata  Schin. 
Tachina  beUa  Meig. 
Tachina  pinivora  Ratz. 
Tachina  larrincola  Ratz. 
Tachina  monacha  Eatz. 
Tachina  noctuarum  R.  D. 
Tachina  quinqnevitala  Hrtg. 
Tachina  rustica  Fall. 
Tachina  larvicola  Hrtg.  (?) 


Tachina  moreti  R,  D. 

Tachina    (Echinomyia)     conjugate 

Rond. 

Tachina  (Echinomyia)  fera  L. 
Tachina  bimaculata  Hrtg. 
Eutachina  larvarum  L. 
Phorocera    concinnata  Meig.  =  M. 

serrieventris  Rond.  (?) 
Sarcophaga  affinis  FalL 
Thelymorpha  vertiginosa  FaU. 
Argyroph}Tlax  gilra  Hrtg. 
Parasitigena  segregata  Rond. 
Macharsea  serriventris  Rond. 
Chsetomyia  crassiseta  Rond, 


It  will  he  observed  that  the  single  species  of  Tachinidae 
thus  far  known  to  infest  Porihetria  di&par,  in  North 
America,  belongs  to  a  different  genus,  or  sub-genus,  from 
any  in  the  above  list,  all  of  which  are  Tachinids  except  one. 
It  will  be  of  interest  to  determine  the  earlier  or  normal  host 
of  Ach  aetoneu  ra  fernaldi. 

Predaceous  Diptera. 

Of  the  predaceous  Diptera  the  following  species  have 
been  taken  feeding  upon  the  imagoes  of  the  gypsy  moth : 
DaJsyTlis  sacrator  Walk.,  attacking  the  females  while  laying ; 
Atilus  tsericeus  Say,  capturing  the  male  imagoes  on  the 
wing. 

Predaceov*  Hemiptera  Heteroptera. 

The  following  account  of  the  predaceous  Hemiptera  Heter- 
optera, known  to  feed  on  the  gypsy  moth,  has  been  prepared 
for  this  report  by  A.  H.  Kirkland,  B.Sc.,  assistant  entomol- 
ogist. 

An  important  factor  in  the  destruction  of  the  gypsy  moth 
caterpillars  is  the  aid  rendered  by  several  species  of  pre- 
daceous bugs,  which,  in  badly  infested  localities,  attack  the 
caterpillars  in  considerable  numbers,  and  in  some  places 
apparently  feed  upon  them  in  preference  to  any  other  kinds 
of  Lepidopterous  larvae.  The  predaceous  bugs  thus  far  found 
feeding  upon  the  gyp*y  moth  are  Podisus  cynicu*  (Say;, 


PREDACEOUS  HEMIPTERA.  393 

P.  serieventris  Uhl.  and  Menecles  insertus  (Say).  Periflus 
circumcinctus  Stal.  has  also,  this  year,  been  doubtfully  re- 
corded, in  a  single  instance,  as  attacking  gypsy  moth  cater- 
pillars. The  following  pages  present  the  facts  we  have 
ascertained  concerning  the  habits  of  each  species,  together 
with  the  life  history  of  P.  serieventris. 

General  Habits. — All  these  species  appear  to  be  arboreal 
in  habits,  although  they  are  occasionally  taken  on  the  ground. 
Their  chosen  food  in  this  region  seems  to  be  the  caterpillars 
of  the  different  Lepidoptera,  and  in  the  search  for  them  the 
bugs  often  climb  trees  to  a  great  height.  The  bugs  seek 
out  caterpillars  in  their  hiding-places  in  the  rough  bark,  or 
even  follow  them  to  their  feeding-places  on  the  foliage,  and 
attack  them  both  during  the  day  and  at  night.  These  pre- 
daceous  insects  possess  a  considerable  degree  of  activity, 
most  noticeable  on  warm  days,  and  have  also  the  ability  to 
exist  for  some  time  without  food,  especially  in  the  earlier 
stages.  During  the  present  summer,  at  the  insectary,  speci- 
mens of  P.  serieventris  were  found  to  be  alive  and  fairly 
active  at  the  end  of  five  days  from  hatching,  without  once 
having  taken  food.  This  marked  degree  of  vitality  of  the 
young  bugs  is  perhaps  not  surprising,  since  from  the  time 
of  hatching  to  the  time  of  first  feeding,  the  element  of  chance 
enters  most  strongly  into  their  career,  for  they  may  often, 
of  necessity,  travel  over  a  large  part  of  a  tree  before 
finding  food  for  the  first  time.  These  species  are  found  on 
all  parts  of  the  trees,  and,  while  they  are  more  or  less  gre- 
garious in  the  first  and  second  stages,  in  the  later  stages 
they  usually  feed  independently  of  each  other.  I  have  re- 
peatedly seen  the  imagoes  of  P.  serieventris  fly  short  dis- 
tances, which  would  indicate  that  this  is  its  ordinary  mode 
of  transit  from  one  tree  to  another.  This  latter  species 
shows  a  considerable  attraction  to  light. 

Of  the  three  species  mentioned,  3f.  insertus  seems  to  be 
the  most  local  in  its  distribution  in  the  infested  district. 
In  the  restricted  areas  in  which  it  occurs  it  is  fairly  abun- 
dant, but  its  limited  distribution  in  the  territory  infested  by 
the  gypsy  moth  renders  it  of  less  importance  than  P.  cynicus 
or  P.  serieventris.  The  two  latter  species  are  very  gener- 


394  THE   GYPSY  MOTH. 

ally  distributed  throughout  the  infested  region,  and  the 
good  they  do  in  destroying  the  caterpillars  of  this  insect  is 
of  no  little  importance.  The  larger  of  the  two  species, 
P.  cynicus,  occurs  in  smaller  numbers  than  P.  serirventris, 
and,  although  it  will  destroy  more  caterpillars  during  its 
feeding  season,  yet  from  the  moderate  numbers  in  which 
it  occurs  it  is  not  so  valuable  an  ally  as  P.  serieventris. 
Whether  these  insects  are  devoured  by  birds  to  any  great 
extent  I  am  unable  to  state.  The  odoriferous  glands  with 
which  they  are  provided  would  seem  to  be  a  means  of  pro- 
tection against  their  natural  enemies.  A  pair  of  crows, 
confined  at  the  insectary,  devoured  all  specimens  offered 
them  of  the  three  species  of  these  bugs,  and  Mr.  Forbush 
informs  me  that  in  nature  these  insects  may  possibly  be 
destroyed  to  some  extent  by  crows,  since  these  birds  are 
known  to  include  the  Heteroptera  in  their  bill  of  fare. 

Method  of  rearing  Predaceous  Bugs.  —  The  problem  of 
breeding  any  Heteropterous  insect  presents  at  the  outset 
many  difficulties,  and  but  little  assistance  is  given  by  the 
literature  on  this  sub-order  of  insects.  Concerning  this  sub- 
ject, Douglas  and  Scott,  in  their  work  on  "  British  Hemip- 
tera,"  Vol.  I,  page  5,  1865,  wrote:  "It  is  probable,  in 
consequence  of  the  fact  that  the  Hemiptera-Heteroptera  are 
in  all  stages  of  their  existence  active  and  suctorial,  and  the 
consequent  difficulty  of  supplying  them,  in  confinement,  with 
fresh,  appropriate  food,  that  but  few  observations  upon  their 
natural  history  have  been  recorded.  .  .  .  But,  whether 
each  species  casts  its  skin  the  same  number  of  times ;  how 
long  the  individuals  of  each  species  remain  as  larva,  pupa 
or  imago ;  what  species  have  more  than  one  brood  in  a 
year,  and  what  constitutes  the  food  of  each  species,  —  are 
matters  that,  in  the  great  majority  of  instances,  remain  to 
be  determined.  There  is,  therefore,  a  wide  field  for  re- 
search in  the  natural  history  of  this  sub-order  of  insects." 

While  considerable  has  been  done  toward  gaining  a 
knowledge  of  the  life  histories  of  many  of  our  plant-feeding 
Heteroptera,  in  the  thirty  years  which  have  elapsed  since 
the  above  was  written,  as  yet  we  know  but  little  of  the  life 
history  of  those  members  of  the  family  which  are  predaceous 


PLATE  61. 


FiG.  10. 

SUFFOLK  ENG.  Co. 


EXPLANATION  OF  PLATE  61. 


Drawn  by  A.  H.  KIRKLAND. 


Podisus  serieventris  Uhl. 

1.  Egg. 

2.  Newly  hatched  nymph. 

3.  Nymph  after  first  molt. 

4.  Spiny  armor  on  surface  of  egg,  greatly  enlarged. 

5.  Curved    spine    from    upper  part    of   egg,  greatly 

enlarged. 

6.  Nymph  after  second  molt. 

7.  Antenna  of  nymph. 

8.  Tarsus  of  nymph. 

9.  Nymph  after  third  molt. 

10.     Out-door  cage  used  in  rearing  this  species. 


PREDACEOUS   HEMIPTERA.  395 

upon  other  insects.  The  first  stumbling  block  met  with,  in 
attempting  to  raise  these  insects,  was  the  provision  of  a 
suitable  breeding-cage,  and  many  attempts  made,  both  dur- 
ing 1894  and  1895,  to  breed  them  in  confinement  in  boxes, 
jars,  etc.,  gave  only  negative  results.  With  the  establish- 
ment of  an  insectary  at  Maiden  and  increased  facilities  for 
out-door  experimentation,  in  June,  1895,  other  attempts 
were  made  to  construct  a  cage  in  which  one  might  rear 
these  insects  under  the  nearest  possible  approach  to  natural 
conditions.  After  several  experiments  a  breeding-cage  was 
devised  which  gave  the  desired  result  (Plate  61,  Fig.  10). 
This  consists  of  a  fine  wire  gauze,  semi-ellipse,  fastened 
tightly  at  the  sides  to  a  small  tree  trunk,  and  closed  at  the 
bottom  by  a  tight-fitting  wooden  base,  the  cage,  on  the 
whole,  being  quite  similar  to  those  used  in  rearing  the  pre- 
daceous  beetles.  The  top  is  covered  by  a  piece  of  cloth, 
held  firmly  in  place  by  a  rubber  band,  while  a  small  wooden 
hoop  is  placed  around  the  inside  of  the  top  of  the  cage,  in 
order  to  prevent  the  band  from  pulling  the  cage  out  of 
shape.  The  cages  used  are  twelve  inches  in  height  by 
four  inches  in  width,  the  maximum  distance  of  the  outer 
part  from  the  tree  being  five  inches.  In  cages  like  the  one 
described  the  bugs  were  fed  on  Lepidopterous  larvas  and 
reared  through  their  different  stages.  For  many  careful 
notes  on  the  feeding  habits  of  these  insects  I  am  indebted 
to  Mr.  H.  L.  Frost,  who  assisted  me  in  the  work.  In 
these  cages  we  were  able  to  successfully  carry  specimens  of 
P.  s'erieventris  through  all  their  transformations. 

Life  History  of  P.  serieventris  Uhl. 
The  Egg.  —  The  eggs  have  been  found  deposited  in  small 
clusters  on  the  bark  of  trees,  en  leaves  and  on  the  burlap 
bands.  When  first  laid  they  are  of  a  glistening,  whitish- 
gray  color,  but  this  soon  changes  to  a  bronze,  which  grows 
darker  as-  the  embryo  develops,  up  to  within  about  a  day 
previous  to  hatching.  At  that  time  the  eggs  grow  lighter 
in  color,  possibly  due  to  the  entrance  of  air  into  the  shell. 
Each  egg-cluster  contains  from  ten  to  thirty  eggs,  two  or 
three  clusters  being  laid  by  each  female.  The  eggs  (Plate 


396  THE   GYPSY  MOTH. 

61,  Fig.  1)  are  ovoid,  .9  mm.  in  length  and  .8  mm.  in 
width.  The  smaller  end  of  the  egg  is  attached  to  the  sur- 
face on  which  the  cluster  is  deposited.  At  the  top  of  the 
egg  is  a  well-defined  circular  cap.  The  greater  part  of  the 
surface  of  the  egg  is  covered  by  irregular  rows  of  minute 
short  spines  (Plate  61,  Fig.  4),  nearly  absent  at  the  base 
of  the  egg,  while  around  the  circumference  of  the  cap  is  a 
row  of  long,  slightly  curved  capitate  spines  (Plate  61,  Fig. 
5),  arranged  in  a  circle.  The  eggs  hatch  in  about  eight 
days.  Four  lots  of  eggs  kept  at  the  insectary  hatched  in 
seven,  eight,  eight  and  nine  days  respectively.  In  hatching, 
the  circular  disk  at  the  top  of  the  egg  is  pushed  back,  but 
usually  remains  attached  at  one  point. 

First  Stage.  —  The  newly  hatched  bug  (Plate  61,  Fig.  2) 
is  1.5  mm.  in  length.  Form,  ovate,  head,  thorax  and  abdo- 
men distinctly  separated.  Head  smooth,  broadly  elliptical, 
wider  than  long,  of  a  deep  copper  color,  and  sparsely  clothed 
with  short,  pale-brown  hairs ;  eyes  large,  projecting  later- 
ally. Antennae  1  mm.  long,  four-jointed,  of  the  same  color 
as  the  head,  but  lighter  at  the  joints,  and  clothed  with  a  few 
hairs.  The  basal  joint  is  stout,  slightly  curved  outward; 
the  second  and  third  joints  are  of  the  same  length  as  the 
basal,  and  each  is  enlarged  at  its  outer  end,  which  is  quite 
sharply  truncate.  The  fourth  joint  is  from  one-fourth  to 
one-third  longer  and  wider  than  the  other  joints,  being  quite 
broadly  dilated.  The  thorax  is  of  the  same  color  as  the 
head,  and  widened  posteriorly.  A  faint  sulcus,  indicated 
by  a  narrow  line,  extends  from  the  centre  of  the  head  down 
the  dorsal  line  of  the  thorax  to  the  abdominal  segments. 
Abdomen  yellowish  red,  varying  to  vermilion.  On  the  dor- 
sum  of  the  abdomen  are  three  large,  dark,  bronze-colored 
spots,  extending  transversely,  and  separated  by  a  narrow 
line  of  the  body  color.  A  short,  narrow  line  of  the  same 
color  as  the  spots  sometimes  occurs  in  front  of  the  anterior 
s^ot,  and  also  immediately  behind  the  posterior  one. 
Around  the  lateral  margin  of  the  abdomen  on  each  side  is 
a  row  of  semi-elliptical  bronze-colored  spots.  Just  ante- 
rior to  the  first  of  these  spots  is  a  narrow,  wedge-shaped 
marking  of  the  same  color,  while  at  the  extreme  posterior 


PREDACEOUS   HEMIPTERA.  397 

end  of  the  abdomen  is  a  larger  horizontal  spot,  which  covers 
the  anal  segments  and  often  connects  the  two  posterior 
lateral  spots.  The  under  surface  of  the  body  is  yellowish 
red,  darkest  on  the  abdominal  segments.  The  lateral  row 
of  semi-elliptical  spots,  similar  to  those  upon  the  upper  sur- 
face, extends  around  the  entire  margin  of  the  abdomen. 
Beak  stout,  four-jointed.  Both  beak  and  legs  are  of  a  dark 
copper  color.  Tarsi  two-jointed  ;  claws  simple,  two  in  num- 
ber, light  brown,  each  with  a  darker  pulvillus ;  legs  sparsely 
clothed  with  pale-brown  hairs. 

The  first  molt  takes  place  in  about  four  days  from  the 
time  of  hatching,  and  is  accompanied  by  a  marked  increase 
in  size. 

Second  Stage.  — The  second  stage  of  this  insect  is  repre- 
sented on  Plate  61,  Fig.  3.  Length,  3.5  mm. ;  body  a  little 
longer  in  proportion  to  the  width  than  in  the  first  stage ; 
head  quadrangular,  with  two  faint  sulci,  extending  backward 
from  the  anterior  margin  for  about  one-third  of  the  length 
of  the  head.  Eyes  prominent.  Basal  joint  of  antennae  short 
and  stout ;  second  joint  cylindrical,  truncate  at  the  end,  twice 
as  long  as  the  basal  joint ;  third  joint  slightly  longer  than 
basal  joint,  and  somewhat  rounded  at  the  outer  end ;  fourth 
joint  appressed  at  each  end,  and  of  nearly  the  same  length 
as  the  second  joint.  The  thorax  is  slightly  serrate  around 
the  outer  margin,  and  its  outer  angles  project  by  the  base 
of  the  head  for  a  short  distance.  The  color  of  the  head  and 
thorax  is  dark  seal  brown,  varying  to  a  pitchy  black.  Ab- 
donien  of  the  same  color  as  in  the  preceding  stage,  but 
with  four  horizontal  spots  instead  of  three,  the  second  and 
third  spots  being  much  larger  than  the  first  and  fourth. 
Lateral  spots  as  in  the  first  stage.  The  under  surface  of 
the  head  and  thorax  is  marked  with  dark  brown,  that  of  the 
abdomen  being  the  same  color  as  in  the  preceding  stage. 
Beak  and  legs  dark  brown,  lighter  on  the  tarsi. 

The  second  molt,  with  an  accompanying  increase  in  size, 
takes  place  from  eight  to  ten  days  after  the  first  molt. 

Third  Stage.  —  The  third  stage  is  represented  by  Plate 
61,  Fig.  6.  Length  of  body,  6  mm.  ;  form  somewhat  ovate, 
narrowest  in  front.  The  head  is  narrowed  from  that  of  the 


398  THE   GYPSY  MOTH. 

preceding  stage,  and  the  eyes  are  very  prominent.  Antenna? 
as  in  the  second  stage.  The  outer  anterior  angles  of  the 
head  are  rounded,  as  well  as  that  part  of  the  anterior  margin 
included  between  the  two  sulci ;  the  latter  extend  backward 
about  one-third  the  length  of  the  head.  The  outer  margin 
of  the  thorax  is  serrated,  as  in  the  preceding  stage.  The 
color  of  the  body  in  this  stage  is  subject  to  great  variation, 
but  brown  or  black  predominates  upon  the  head  and  thorax 
and  some  shade  of  red  upon  the  abdomen.  Usually  the  head 
and  thorax  are  margined  with  a  narrow,  pale-yellowish-white 
line,  while  four  small  spots  of  pale-yellowish  brown  occur 
on  opposite  sides  of  the  dorsal  line  of  the  pro-thorax,  and 
two  spots  of  the  same  color  on  each  side  of  the  dorsal  line 
of  the  meso-thorax.  The  abdomen  bears  the  same  markings 
as  in  the  preceding  stages,  but  the  ground  color  varies  to  a 
considerable  degree.  From  each  side  of  each  dark  marginal 
spot  a  creamy- white  line  extends  in  towards  the  large  dorsal 
spots.  In  some  cases  these  lines  are  very  wide,  and  give  to 
the  abdomen  a  very  light  and  somewhat  striped  appearance  ; 
in  other  cases  they  are  nearly  obscured  by  the  red  ground 
color.  The  beak,  legs  and  under  surface  of  the  body  are 
marked  the  same  as  in  the  second  stage.  As  the  nymph  of 
the  third  stage  approaches  the  molting  period,  the  outlines 
of  the  scutellum  and  wing  pads  become  somewhat  apparent. 
The  third  molt  occurs  from  five  to  six  days  after  the  pre- 
ceding one. 

Fourth  Stage.  —  This  stage  is  shown  on  Plate  61,  Fig.  9. 
Length  of  body,  8.5  mm.  General  form  of  body,  aside  from 
head,  nearly  elliptical,  slightly  widened  posteriorly.  Head 
with  two  deep  sulci,  and  closely  appressed  to  the  anterior 
margin  of  the  thorax.  Antennae  as  in  the  preceding  stage, 
the  second  joint  much  the  longest.  The  yellow  marginal 
band  of  the  head  and  thorax  is  wider  than  in  the  third  stage, 
otherwise  the  colors  of  the  upper  surface  of  the  body  are  the 
same  as  those  of  the  third  stage.  The  under  surface  of  the 
body  sometimes  varies  to  a  brownish  tint,  but  in  general  it 
is  like  that  of  the  preceding  stage.  The  color  of  the  legs 
and  beak  is  not  changed  from  that  of  the  third  stage.  The 
wing  pads  and  scutellum  appear  in  this  stage.  Xymphs  in 


PREDACEOUS   HEMIPTEEA.  399 

i 

the  fourth  stage  show  great  rapacity,  and  a  corresponding 
growth  is  made. 

The  fourth  and  last  molt  takes  place  in  from  twelve  to 
seventeen  days  from  the  third  molt,  and  the  insect  attains 
the  imago  form. 

Fifth  Stage,  or  Imago. — The  following  is  Professor 
Uhler's  original  description  of  this  species,  taken  from 
"Proceedings  of  the  Boston  Society  of  Natural  History," 
page  94,  Vol.  XIV.,  1870:  — 

"  P.  serieventris,  n.  sp.  Similiar  to  P.  modestus  Dallas, 
but  of  a  more  blackish-gray  color.  Pronotum,  sides  less 
deeply  sinuated,  the  humeral  angles  not  so  prominent,  ob- 
tusely triangular,  blackish ;  the  surface  less  regularly  punct- 
ured, those  each  side  anteriorly  and  in  the  corners  finer, 
confluent,  presenting  the  appearance  of  four  blackish  spots, 
the  middle  surface  somewhat  bald,  yellow.  Scapus  and  basal 
joint  of  the  antennae  blackish  outwardly.  Scutellum  punct- 
ured with  black,  the  punctures  at  the  base  aggregated  in  a 
large  patch,  the  basal  angles  with  a  large,  smooth,  whitish 
spot,  the  tip  smooth,  white.  Pectus  remotely  punctured 
with  fuscous,  the  impressed  portion  of  the  propleura,  the 
middle  of  the  mesopleura  and  exterior  part  of  the  metapleura 
with  a  large  patch  of  black,  confluent  punctures,  the  exterior 
margin  smooth ;  exterior  end  of  the  osteolar  duct  black,  the 
sulcus  broad,  not  reaching  to  the  tip.  Legs  pale  orange 
yellow,  the  femora  pointed  with  black,  the  dots  more  or  less 
aggregated  beyond  the  middle.  Corium  less  coarsely  punct- 
ured, the  punctures  fuscous  or  rufous ;  those  of  the  costal 
area  coarser,  the  finer  ones  aggregated  in  small  patches ; 
the  surface  adjoining  the  inner  surface  and  tip  of  the  medium 
suture  smooth,  with  a  more  or  less  embrowned  spot  before 
the  tip  ;  embolium  yellow,  with  a  fuscous  spot  at  base  ;  the 
membrane  tinged  with  brown ;  the  basal  margin,  nervures 
basally,  and  a  broad,  longitudinal  streak  running  to  the  tip, 
blackish.  Tergmn  with  large  clouded  spots  each  side  and 
behind ;  connexivum  bright  yellow  above,  with  a  quadran- 
gular black  spot  at  the  base  and  apex  of  each  segment,  on 
the  under  side  having  a  corresponding  series  of  spots  which 
are  sometimes  reduced  to  mere  dots.  Venter  punctured 


400  THE   GYPSY  MOTH. 

with  rufous  and  black,  the  latter  arranged  each  side  in  a 
longitudinal  series  of  patches ;  interior  to  these  is  a  row  of 
black  spots,  and  upon  the  middle  line  four  round  spots,  with 
the  largest  one  at  the  posterior  end. 

"Length  to  tip  of  abdomen,  9  inillims.  Humeral  width, 
5  millims. 

"  No.  40,  Harris  Collection  $  .  '  Cambridge,  Mass.,  April 
20,  1827.' 

' '  The  specimens  vary  very  much  in  depth  of  color  and  in 
the  size  and  distinctness  of  the  markings. 

"In  my  own  collection  are  specimens  from  Maine  and 
Minnesota.  A  female  from  Massachusetts  is  twelve  millims. 
in  length." 

In  the  imago  state  the  antennae  and  tarsi  (Plate  62,  Figs. 
4  and  5)  are  increased  by  an  additional  joint,  and  become 
respectively  five  and  three  jointed.  The  imago  varies  in 
color  from  a  blackish  gray  to  a  light  brownish  gray,  though 
none  of  the  specimens  so  far  taken  or  reared  are  of  as  light 
color  as  P.  modestus  Dall.  The  males  (Plate  62,  Fig.  1), 
as  a  rule,  are  slightly  smaller  than  the  females  (Plate  62, 
Fig.  2),  and  their  humeral  angles  are  somewhat  sharper, 
more  nearly  approaching  those  of  P.  spinosus  Dall. 

For  the  identification  of  the  specimens  reared  at  the  in- 
sectary  I  am  indebted  to  the  courtesy  of  Prof.  P.  R.  Uhler. 

The  following  extract  from  notes  upon  an  individual  of 
the  third  brood,  reared  from  eggs  laid  Aug.  14,  1895,  will 
serve  to  illustrate  the  life  history  of  a  single  generation : 
Predaceous  bug,  No.  142,  Podisus  serieventris  Uhl. 

Hatched  August  22  ;  the  first  molt  occurred  August  26. 
Up  to  this  date  the  bug  had  been  fed  upon  the  remains  of 
four  climbing  cut-worms  (JVbctua  c-nigrum}.  The  second 
molt  took  place  September  3.  Between  the  first  and  second 
molt  it  killed  four  larvae  of  Noctua  c-nigrum  and  two  larvae 
of  Khynchagrotis  alternata.  The  bug  molted  for  the  third 
time  September  8,  having  killed  in  the  mean  time  two  full- 
grown  caterpillars  of  Vanessa  antiopa  and  two  of  Anisota 
senatoria.  The  fourth  molt  occurred  September  21. 
Between  the  third  and  fourth  molt  it  had  killed  eight  full- 
grown  caterpillars  of  Vanessa  antiopa,  two  larvae  of  Ani- 


EXPLANATION    OF    PLATE    62. 


Drawn  by  A.  H.  KIRKLAND. 


Podisus  serievcntris  Uhl. 

1.  Male  imago.  4.  Antenna  of  imago. 

2.  Female  imago.  5.  Tarsus  of  imago. 

3.  Rostrum  of  imago.  6.  Wings  of  imago. 


PLATE  62. 


SUFFOLK  ENG.  Co. 


PREDACEOUS   HEMIPTERA.  401 

sofa  senatoria  and  one  partly  grown  larva  of  Telea  polyplie- 
mus.  In  the  imago  stage  the  insect  (female)  killed  five 
larvae  of  Anisota  senatoria.  It  was  placed  with  a  male  Sep- 
tember 25,  and  mated  September  30.  On  October  12,  it 
was  found  partly  hidden  under  some  loose  bark  and  leaves 
which  had  been  placed  in  the  bottom  of  the  breeding-cage, 
and  at  the  present  writing  (Jan.  1,  1896)  it  is  still  alive,  and 
hibernating  without  having  deposited  its  eggs. 

Feeding  Habits.  —  In  attacking  a  full-grown  larva  the 
bug  apparently  first  makes  a  preliminary  investigation,  and, 
with  antennae  elevated,  carefully  inspects  the  caterpillar  on 
all  sides.  After  sidling  around  for  some  time,  the  point  of 
attack  is  selected,  usually  the  softer  integument  at  the  an- 
nulations  of  the  body,  the  beak  (Plate  62,  Fig.  3)  is  swung 
down  and  out,  projected  horizontally  forward  and  inserted 
in  the  side  of  the  larva.  Its  entrance  is  at  first  unnoticed 
by  the  caterpillar,  but  after  a  few  minutes  a  vigorous  struggle 
ensues,  which  sometimes,  but  rarely,  results  in  the  bug  being 
obliged  to  release  its  hold.  In  a  short  time  the  caterpillar 
grows  weaker,  apparently  becomes  stupefied,  and  the  bug, 
after  inserting  its  beak  in  new  places,  till  the  greater  part 
of  the  body  fluids  have  been  extracted,  finally  leaves  the 
dead,  empty  and  flaccid  larva  hanging  to  the  tree.  The 
time  consumed  in  feeding  on  a  full-grown  gypsy  moth 
caterpillar  varies  from  ten  minutes  to  two  or  three  hours, 
the  bug  as  a  rule  feeding  longest  upon  the  thoracic  seg- 
ments. 

The  newly  hatched  bug  seems  to  be  unable  to  cope  with 
large  caterpillars,  and  I  am  led  to  believe  that  under  natural 
conditions  their  early  food  is  small  larvae.  On  June  10, 
1895,  at  Winthrop,  Mass.,  I  found  twelve  nymphs  of  P. 
serieventris,  of  the  first  and  second  stage,  feeding  upon 
small,  dark  beetle  larvae,  which  were  abundant  upon  leaves 
of  Plantago  major.  In  the  breeding  cage  the  young  nymphs 
were  first  fed  upon  the  remains  of  soft-skinned  larvae,  such 
as  Rhynchagrotis  alternata  and  Noctua  c-nigrum,  the  cater- 
pillars being  cut  up  into  small  bits  before  feeding  them  to  the 
bugs.  It  was  necessary  to  place  the  young  bugs  in  close 
proximity  to  the  food  thus  provided,  and  for  this  purpose  a 


402  THE   GYPSY  MOTH. 

small  camel's-hair  brush  was  found  to  be  of  great  assistance. 
After  passing  the  first  molt  the  nymphs  were  able  to  care 
for  themselves,  and  would  boldly  attack  full-grown  cut- 
worms, of  the  species  mentioned,  when  the  latter  were 
placed  in  the  cages.  With  increasing  age  and  size  they  fed 
readily  upon  hairy  larvae  (P.  dispar,  Tolype  veUeda,  et  a?.). 
The  period  of  greatest  rapacity  and  of  greatest  growth  is 
between  the  third  and  fourth  molt,  during  which  time  the 
nymph  feeds  almost  continuously. 

This  insect  has  been  taken  in  the  field  attacking  all  stages 
of  the  gypsy  moth.  Individuals  in  the  first  stage  were  this 
year  found  feeding  upon  the  eggs  of  the  gypsy  moth,  but 
when  confined  to  this  food  died  at  the  end  of  a  few  days. 
It  is  not  an  uncommon  thing  for  them  to  attack  a  pupa,  and 
on  one  occasion  I  found  four  nymphs  in  the  second  and  third 
stages  feeding  upon  a  single  female  pupa.  Female  gypsy 
moths  while  depositing  their  egg-clusters,  and  males  while 
mating,  are  also  occasionally  attacked  by  this  insect. 

This  species  has  been  found  feeding  upon  the  larvae  of 
Vanessa  antiopa,  Hyphantria  cunea,  Orgyia  leucostigma, 
Attacus promethea,  Clisiocampa  americana  and  disstria  and 
Paleacrita  vernata.  It  has  also  been  known  to  devour  the 
dead  imagoes  of  Limenitis  Ursula  and  Pyrophila  pyrami- 
doides.  In  confinement  it  readily  attacks  the  larvae  of 
Datana  ministra,  Attacus  cecropia,  Telea  polyphemus, 
Anisota  senatoria,  Dryocampa  rubicunda,  Tolype  velleda, 
Rhynchagrotis  alternata,  Noctua  c-nigrum  and  Cimbex 
americana. 

When  pressed  by  hunger  these  insects  develop  cannibal 
tendencies  and  feed  upon  other  individuals  of  the  same 
species,  and  also  occasionally  attack  Podisus  cynicus  and 
Menecles  insertus,  while  the  two  latter  species  have  in  turn 
been  found  feeding  upon  P.  serieventris.  I  have  seen  P. 
serieventris  feeding  in  confinement  upon  leaves  of  Quercus 
rubra,  but  I  think  it  very  doubtful  if  it  is  phyllophagous  to 
any  marked  degree. 

Mating  —  Polygamy  —  Oviposition.  —  Mating  takes  place 
in  from  three  to  six  days  from  the  time  the  insect  reaches 


PREDACEOUS  HEMIPTERA.  403 

the  imago  state.  The  time  required  for  the  process  of 
mating  varies  from  twelve  to  forty-eight  hours. 

That  the  males  of  this  species  are  polygamous  is  evident 
from  the  fact  that  one  male  confined  in  a  breeding  cage  at 
the  insectary  successfully  fertilized  three  females.  With  the 
exception  of  the  females  of  the  last  brood,  oviposition  takes 
place  in  from  eight  hours  to  two  or  three  days  from  the 
time  of  mating.  The  female  deposits  a  cluster  of  from  ten 
to  thirty  eggs,  then  rests  and  feeds  for  a  few  hours,  but  later 
resumes  the  work  of  egg-laying.  In  this  way  some  three 
or  four  clusters  of  eggs  are  deposited,  the  whole  process  of 
egg-laying  usually  taking  from  one  to  four  days. 

Hibernation. — That  the  insect  hibernates  in  the  imago 
state  seems  to  be  an  assured  fact,  since  specimens  of  the 
last  brood  reared  at  the  insectary,  and  left  in  the  breeding 
cages  out  of  doors,  are  alive  at  the  time  of  this  writing 
(Jan.  1,  1896).  The  imagoes  of  the  last  brood  mate  soon 
after  reaching  the  mature  form,  and  the  fertilized  females 
feed  at  intervals  for  a  week  or  two  ;  but  with  the  advent  of 
cooler  weather  seek  hibernating  quarters,  such  as  the  crev- 
ices in  the  rough  bark  of  trees,  under  burlap  bands,  etc.,  or 
even  under  the  dead  leaves  upon  the  ground,  sometimes 
burying  themselves  one  or  two  inches  beneath  the  surface. 
All  of  the  males  reared  during  the  past  year  died  without 
attempting  to  hibernate. 

Number  of  Annual  Broods.  During  the  summer  of  1895, 
imagoes  of  this  species  were  more  or  less  abundant  about  the 
last  of  June  and  the  middle  of  August,  and  in  fewer  numbers 
from  the  middle  to  the  last  of  September,  although  individ- 
uals were  taken  throughout  the  summer.  Nymphs  were 
found  in  considerable  numbers  at  such  intervals,  subsequent 
to  the  appearance  of  the  imagoes,  as  would  lead  one  to  believe 
that  they  were  distinct  broods.  I  have  reared  two  broods 
of  this  species  between  the  last  of  June  and  the  latter  part 
of  September ;  and  this,  in  connection  with  the  facts  that 
young  nymphs  have  been  found  in  early  June,  and  that  the 
fertilized  female  imagoes  of  the  last  brood  hibernate,  would 
seem  to  be  nearly  conclusive  evidence  that  the  species  is 
three-brooded  in  this  region. 


404  THE   GYPSY  MOTH. 

Spiders. 

At  occasional  intervals  during  the  past  four  years,  spiders 
have  been  seen  to  attack  and  destroy  the  eggs,  and  also  the 
caterpillars  and  imagoes,  of  P.  dispar.  In  the  summer  of 
1895,  a  predaceous  spider,  found  in  Chelsea,  was  brought 
into  the  insectary  and  supplied  with  gypsy  moth  cater- 
pillars, which  it  readily  destroyed.  This  spider  was  kindly 
determined  by  Mr.  J.  H.  Ernerton  as  Phidippustripunctatus. 

Our  common  harvest  spider  (Phalangium  dorsatutn)  was 
found  by  Mr.  Mosher  feeding  on  a  male  gypsy  moth. 

Mites  have  been  found  so  frequently  destroying  the  eggs 
that  we  must  acknowledge  that  in  some  localities  they  are 
very  important  factors  in  reducing  the  numbers  of  the  gypsy 
moth.  Mr.  E.  P.  Felt  observed  the  work  of  these  mites  on 
the  gypsy  moth  eggs  in  confinement,  and  found  that  they 
destroyed  the  eggs  very  rapidly.  They  are  most  abundant 
in  the  fall,  but  do  not  feed  to  any  marked  degree  during 
the  winter.  These  mites  were  referred  to  Prof.  Herbert 
Osborn,  who  determined  them  as  two  different  species.  The 
first  was  Nothrus,  near  ovivorus  Pack.  (Plate  53,  Fig.  14), 
and  the  other  was  Trombidium  bulbipes  Pack.  (Plate  53, 
Fig.  15).  A  species  of  Phloeothrips  (Plate  63,  Fig.  13)  was 
also  found  destroying  the  eggs. 

Insectivorous  Vertebrates. 

Of  the  vertebrate  enemies  of  the  gypsy  moth,  the  common 
skunk,  Mephitis  mephitica  (Shaw),  has  been  found  feeding 
upon  the  female  moths  which  were  laying  their  eggs  at  the 
base  of  trees,  or  upon  rocks,  rubbish,  etc.  It  is  probable 
that  these  animals  also  feed  upon  the  pupae  to  some  extent 
in  badly  infested  regions. 

The  wood  frog  (Rana  silvatica  LeC.)  has  been  reported 
in  one  instance  as  attacking  the  female  moths.  In  August, 
1895,  Mr.  F.  H.  Mosher  took  a  specimen  of  the  tree  frog 
(Hyla  pickeringii  Holbr.),  feeding  upon  the  caterpillars 
of  the  second  brood  of  the  gypsy  moth,  at  Woburn. 

The  common  garden  toad  (Bufo  lentiginosus  americanus 
LeC.)  was  this  year  found  by  Mr.  Kirkland  to  be  devouring 


VEGETABLE  PARASITES.  N     405 

great  numbers  of  the  caterpillars  in  infested  brushlands. 
Stomach  examinations  of  three  toads,  taken  in  such  a  place, 
June  6,  1895,  showed  them  to  contain  respectively  seven, 
fifteen  and  sixty-five  gypsy  moth  caterpillars,  or  remains  of 
the  same. 

Mr.  Samuel  Henshaw  published  a  report  upon  the  gypsy 
moth  in  Massachusetts,  in  Bulletin  No.  26,  United  States 
Department  of  Agriculture,  Division  of  Entomology,  page 
75,  in  which  he  gives  the  following  list  of  invertebrates  that 
destroy  the  larvae  of  the  gypsy  moth  :  Cicindela  6-guttata, 
Camponotus  herculaneus,  Sinea  diadema,  and  undetermined 
Syrphus,  and  Chrysopa,  Litholius  forficatus ;  also  the  fol- 
lowing spiders  :  JEpeira  strix,  Steatoda  borealis,  Lycosa  sp., 
Drassus  sp.,  Agalena  ncevia,  Phidippus  galathea  (mysta- 
ceus),  Epiblemum  scenicum,  Marptusa  familiaris  and 
Thomixus  sp. 

Mr.  Henshaw's  letter  of  submittal  is  dated  "Cambridge, 
Mass.,  Dec.  7,  1891,"  and  therefore  his  observations  were 
probably  made  during  the  summer  of  1891. 

VEGETABLE  PARASITES. 

A  very  careful  watch  has  been  kept  for  any  indication  of 
vegetable  parasites,  either  fungi  or  microbes,  and  nothing 
has  thus  far  been  discovered.  We  consulted  with  Drs. 
Farlow  and  Thaxter  of  Harvard  University,  both  eminent 
authorities  on  the  subject,  and,  after  describing  to  them  the 
habits  of  the  insect,  neither  of  these  gentlemen  gave  us  en- 
couragement that  vegetable  parasites  would  prove  to  be  a 
very  important  factor  in  the  destruction  of  the  gypsy  moth ; 
yet,  in  wet  seasons,  where  the  caterpillars  were  very  abun- 
dant, the  parasitic  fungi,  if  any  could  be  found  to  attack  this 
species,  might  prove  more  or  less  serviceable. 

The  caterpillars  of  the  nun  moth  (Lymantria  monacha), 
in  Europe,  when  very  abundant,  are  often  attacked  by  an 
epidemic  or  contagious  disease  known  as  the  top  or  head 
sickness  ( Wipfelkrankheit) ,  a  very  good  account  of  which 
has  been  given,  by  Wachtl  and  Kornauth  in  their  '  *  Beitrage 
zur  Kenntniss  der  Morphologic,  etc.,  der  Xonne,"  page  17. 
Drs.  Tangl,  Scheuerlen,  Hofinann,  Tubeuf  and  Jager  have 


406  THE   GYPSY  MOTH. 

made  careful  investigations  of  this  disease,  but  have  had 
very  little  success  in  inoculating  healthy  caterpillars  with 
cultures  made  from  those  which  were  diseased. 

IMPORTING  PARASITES. 

No  attempt  has  been  made  to  import  parasites  thus  far, 
for  the  reason  that  the  law  requires  the  work  to  be  con- 
ducted with  direct  reference  to  the  extermination  of  the 
gypsy  moth,  and,  therefore,  the  general  destruction  of  the 
insect  would  also  destroy  the  parasites.  There  is  no  reason 
why  our  native  Hymenopterous  parasites  may  not  prove 
quite  as  effective  as  those  of  any  other  country,  since  there 
is  no  parasite  known  which  confines  itself  exclusively  to  the 
gypsy  moth,  and,  as  has  been  shown,  we  have  several  species 
which  attack  it  as  readily  as  any  in  its  native  country. 

IXSECTARY. 

In  the  early  part  of  the  work  on  the  gypsy  moth,  the 
more  difficult  and  important  experiments  and  observations 
were  conducted  in  the  insectary  at  Amherst ;  but  it  seemed 
desirable,  and  even  necessary,  to  repeat  many  of  the  ex- 
periments on  a  far  more  extensive  scale  than  was  possible 
at  that  place,  and  it  was  therefore  decided  to  fit  up  and  equip 
a  room  for  this  purpose,  in  the  store-house  on  Commercial 
Street,  Maiden.  This  building  stands  on  piles,  about  six 
feet  from  the  ground,  which  is  swampy  and  wet.  The  front 
of  the  building  is  on  a  level  with  the  street,  which  is  built 
up  to  the  grade  indicated. 

In  the  room  thus  fitted  up  many  experiments  were  con- 
ducted, a  large  number  of  which  gave  very  satisfactory 
results.  But  in  the  experiments  on  insecticides,  where  a 
check  series  was  conducted,  with  no  poisons  used  on  the 
food,  the  mortality  was  often  so  great  that  we  felt  very  un- 
certain about  the  results  in  the  cages  where  the  caterpillars 
were  fed  on  leaves  sprayed  with  insecticides,  whether  they 
died  from  the  effects  of  the  poison,  or  because  of  the  un- 
healthful  surroundings. 

In  the  early  part  of  the  summer  of  1895,  a  small  lot  of 
land,  in  the  edge  of  the  woodland  in  the  suburbs  of  Maiden, 


PLATE  63.     Experiment  station  and  insectary,  Maiden,  Mass. 


INSECTICIDES.  407 

was  leased,  and  an  insectary  was  erected  for  experimental 
purposes.  This  building  (Plate  63)  is  sixteen  by  twenty 
feet  on  the  ground,  with  a  greenhouse  on  the  south  side,  six 
by  eight  feet,  and  a  covered  shed  on  the  north  side,  seven 
by  eight  feet.  It  contains,  on  the  first  floor,  besides  the 
main  laboratory  with  tables,  closets,  etc.,  a  private  labora- 
tory and  a  chemical  room.  The  second  floor  contains  a 
lodging-room  for  the  employees. 

The  experimental  work  carried  on  in  this  building,  during 
the  summer  of  1895,  has  proved  far  more  satisfactory  than 
that  in  the  building  on  Commercial  Street,  because  of  the 
greater  conveniences  and  more  healthful  conditions. 

INSECTICIDES. 
Experiments  with  Substances  for  destroying  Eggs. 

The  value  of  egg-destruction,  as  an  exterminative  meas- 
ure, was  recognized  at  an  early  stage  in  the  work  of  com- 
bating the  gypsy  moth,  and  led  to  an  extensive  study  of 
substances  which  might  be  advantageously  used  for  this 
purpose.  The  requisites  necessary  in  such  a  substance  are  : 
that  it  shall  be  effective  wherever  applied ;  that  it  shall 
leave  a  permanent  stain  or  color,  enabling  one  to  distinguish 
treated  from  untreated  egg-masses ;  and  that  its  price  shall 
be  within  practical  limits.  The  substances  found  to  be 
of  the  greatest  value,  together  with  an  explanation  of  the 
method  of  applying  them,  have  already  been  described  in 
Part  I. 

During  the  year  1892,  Mr.  F.  C.  Moulton  experimented 
with  the  following  substances  on  the  eggs  of  the  gypsy 
moths,  to  discover  something  that  could  be  readily  applied 
to  the  egg-clusters  and  effectually  destroy  them.  To  some 
of  the  preparations  were  added  substances  which  contain  no 
destructive  power,  but  were  used  simply  to  change  the  color 
of  the  egg-clusters  on  trees,  so  that  those  which  had  been 
treated  might  be  readily  distinguished  from  the  others. 

Ammonia.  — January  21.  Five  egg-clusters  were  treated 
for  five  minutes  with  ammonia  gas,  made  by  heating  strong 
aqua-ammonia.  Apparently  the  eggs  were  not  affected,  for, 
by  March  24,  nearly  all  had  hatched. 


408  THE   GYPSY   MOTH. 

Benzine.  — January  22.  A  small  amount  of  benzine  was 
poured  upon  an  egg-cluster  and  then  allowed  to  evaporate. 
Apparently  the  eggs  were  not  affected,  for  by  March  24, 
about  three-tenths  of  them  had  hatched.  Nearly  five-tenths 
of  the  caterpillars  died  while  hatching. 

Bromine. — January  19.  Five  egg-clusters  were  placed 
in  a  box  and  a  small  amount  of  liquid  bromine  turned  on 
them.  At  the  end  of  fifteen  minutes  they  were  entirely 
destroyed. 

Bromine  Vapor. — January  19.  Five  egg-clusters  were 
submitted  to  the  action  of  bromine  vapor  in  a  closed  box 
for  ten  minutes.  At  the  end  of  this  time  the  eggs  were 
destroyed.  Another  experiment  on  the  same  date,  in  which 
the  eggs  were  exposed  for  fifteen  minutes,  gave  similar  re- 
sults. From  egg-clusters  treated,  on  the  same  date,  with 
bromine  vapors  for  a  period  of  ten  minutes,  the  vapor  not 
being  closely  confined,  a  few  caterpillars  hatched.  Four 
caterpillars  hatched  from  other  egg-masses  treated  in  the 
same  manner. 

Chlorine.  — January  15.  One  egg-cluster  was  submitted 
for  five  minutes  to  the  action  of  chlorine  gas,  made  by  add- 
ing ten  parts  (by  weight)  of  hydrochloric  acid  to  eight 
parts  of  black  oxide  of  manganese,  and  then  applying  a 
strong  heat  to  the  mixture.  The  egg-cluster  was  bleached 
and  the  eggs  destroyed.  Four  other  experiments,  in  which 
egg-clusters  were  exposed  to  the  action  of  chlorine  for 
seven,  ten,  fifteen  and  thirty  minutes  respectively,  gave 
similar  results.  March  12.  Some  chloride  of  lime  was  put 
into  a  flask  and  sulphuric  acid  added  to  it.  The  chlorine 
was  then  conducted  into  a  bottle  containing  gypsy  moth 
egg-clusters.  It  entirely  destroyed  the  eggs,  with  but  one 
exception.  January  19.  Five  egg-clusters  were  treated 
with  chlorine  under  a  hood  made  of  oil-cloth  stretched  over 
a  frame,  but,  as  the  oil-cloth  was  not  large  enough  to  en- 
tirely cover  it,  a  part  of  the  gas  escaped.  One  egg-cluster 
was  bleached,  while  the  others  were  apparently  not  affected ; 
about  one-third  of  the  eggs  hatched  the  following  spring. 

Carbon  Bi-sulphide.  —  January  19.  Five  egg-clusters 
were  submitted  to  the  action  of  hot  vapors  of  carbon  bi-sul- 


INSECTICIDES.  409 

phide  for  five  minutes.  The  carbon  bi-sulphide  was  put 
into  a  flask  and  slightly  heated,  the  vapors  passing  over  a 
bottle  containing  the  egg-clusters,  condensing  and  wetting 
them,  which  caused  the  eggs  to  become  white  and  soft,  after 
which  they  all  dried  up.  Two  lots  of  eggs  exposed  to  the 
vapors  of  carbon  bi-sulphide,  in  a  similar  manner,  for  ten 
and  fifteen  minutes  respectively,  were  completely  destroyed. 
January  19.  Five  egg-clusters,  placed  in  a  tin  box  covered 
with  paper,  were  treated  for  fifteen  minutes  with  carbon  bi- 
sulphide, which  caused  them  to  grow  white  and  soft,  thus 
destroying  them.  January  21.  Five  egg-clusters  were 
treated  with  cold  vapors  of  carbon  bi-sulphide  for  fifteen 
minutes,  care  being  taken  that  the  vapors  should  not  wet 
the  egg-clusters.  The  eggs  apparently  were  not  affected, 
and,  by  the  24th  of  March,  about  one-half  of  them  had 
hatched.  January  25.  Five  egg-clusters  were  treated  for 
fifteen  minutes  to  the  action  of  cold  vapors  of  carbon  bi-sul- 
phide. The  eggs  were  placed  in  a  glass,  which  was  put  in 
a  large  tin  box  containing  carbon  bi-sulphide.  The  eggs 
were  not  affected  by  this  treatment,  and,  by  the  24th  of 
March,  all  had  hatched.  February  9.  A  number  of  egg- 
clusters  were  treated  in  the  same  manner  as  in  the  preced- 
ing experiment,  and,  although  the  eggs  did  not  appear  to 
be  affected,  none  hatched. 

Calcic  Chloride. — January  21.  One  egg-cluster  was 
soaked  for  half  a  day  in  a  solution  of  calcic  chloride,  made 
by  dissolving  one-eighth  ounce  of  calcic  chloride  in  two 
cubic  centimeters  of  water.  The  solution  did  not  penetrate 
the  egg-cluster,  and  nearly  all  the  eggs  hatched. 

Corrosive  Sublimate.  —  February  1 .  A  few  crystals  of 
corrosive  sublimate  were  dissolved  in  alcohol,  and  the  solu- 
tion poured  over  five  egg-clusters.  March  22,  some  of  the 
eggs  had  partly  hatched,  but  the  caterpillars  soon  died. 
February  1.  Five  egg-clusters  were  treated  in  the  same 
manner  as  in  the  preceding  experiment.  Two  or  three 
caterpillars  hatched  and  others  came  partly  out  of  the  shell, 
but,  March  22,  all  were  dead.  Three  other  lots  of  eggs  were 
treated  in  the  same  manner,  March  3.  None  of  these  eggs 
hatched. 


410  THE   GYPSY  MOTH. 

Creosote  Oil. — March  14.  A  small  amount  of  creosote 
oil  was  dropped  upon  five  egg-clusters,  and,  although  it  did 
not  appear  to  injure  the  eggs,  none  of  them  hatched.  March 
31.  A  mixture  of  creosote  oil  and  pine  tar,  fifty  per  cent, 
of  each,  was  dropped  upon  some  egg-clusters.  It  pene- 
trated them  at  once,  and,  later,  shrivelled  the  eggs  so  that 
none  hatched.  March  3 1 .  Another  lot  of  egg-clusters  was 
treated  in  the  same  manner,  and  the  eggs  destroyed.  Two 
experiments  with  a  mixture  of  creosote  oil,  fifty  per  cent., 
and  turpentine,  fifty  per  cent.,  gave  results  like  those  of  the 
preceding  experiments.  April  7.  About  eight  thousand 
eggs  were  saturated  with  a  solution  of  pine  creosote  oil, 
forty-five  per  cent.,  turpentine,  forty-five  per  cent.,  and 
coal  tar,  ten  per  cent.  It  penetrated  the  egg-clusters  read- 
ily, and  attacked  the  eggs  so  that  none  hatched. 

Goal  Tar.  —  March  5.  A  mixture  of  coal  tar,  thirty  per 
cent. ,  phenol,  forty  per  cent. ,  and  turpentine,  thirty  per  cent. , 
was  dropped  upon  ten  egg-clusters.  It  quickly  penetrated 
the  eggs,  turning  them  black  and  softening  the  shell  so  that 
none  hatched.  Several  other  experiments  with  similar  tar 
mixtures  gave  equally  as  satisfactory  results. 

Eagle  Mills  Powder. — March  11.  A  mixture  of  Eagle 
Mills  Powder,  fifty  per  cent.,  and  turpentine,  fifty  per  cent., 
was  dropped  upon  ten  egg-clusters,  but  the  mixture  was  too 
thick  to  penetrate.  March  11.  A  solution  of  Eagle  Mills 
Powder,  ten  per  cent.,  water,  sixty  per  cent.,  and  alcohol, 
thirty  per  cent.,  was  dropped  on  some  egg-clusters,  and 
quickly  penetrated  to  the  bottom.  This  did  not  injure  the 
eggs,  for,  by  April  12,  nearly  all  had  hatched. 

Hydrocyanic  Acid  Gas. — January  11.  One  egg-cluster 
was  submitted  to  the  action  of  pure  concentrated  hydro- 
cyanic gas,  in  the  following  apparatus  :  A  Florence  flask, 
containing  one-half  an  ounce  of  potassium  cyanide  and  about 
twenty  cubic  centimeters  of  water,  was  connected  with  a 
wide-mouthed  bottle  by  a  tube  bent  twice  at  right  angles. 
The  bottle  also  contained  an  escape  tube.  An  unbroken 
egg-cluster  was  placed  in  the  bottle,  then  sulphuric  acid  was 
added  to  the  potassium  cyanide  in  the  flask.  The  hydro- 
cyanic acid  gas  passed  over  into  the  bottle,  driving  the  air 


INSECTICIDES.  411 

out  through  the  delivery  tube.  After  the  air  was  all  out, 
the  delivery  tube  was  stopped  by  a  cork ;  and,  as  the  action 
was  still  going  on,  the  gas  in  the  apparatus  was  under  pres- 
sure and  remained  so  for  thirty  minutes,  when  the  egg- 
cluster  was  removed.  No  change  could  be  detected,  either 
with  the  naked  eye  or  by  use  of  the  microscope,  and,  by 
March  24,  about  one-half  of  the  eggs  had  hatched.  On  the 
same  date,  nine  other  egg-clusters  were  treated  in  the  same 
manner,  using  the  same  apparatus  under  the  same  condi- 
tions. An  examination  of  the  eggs  failed  to  show  any 
change.  These  eggs  hatched  February  6.  January  12. 
Five  egg-clusters  were  treated  with  hydrocyanic  acid  gas, 
for  thirty  minutes,  under  a  hood  made  by  spreading  oil- 
cloth over  three  bottles.  The  edge  of  the  cloth  came  down 
to  the  .table,  but  not  close  enough  to  exclude  the  air,  as  there 
were  numerous  crevices  under  the  cloth.  The  density  of 
hydrocyanic  acid  gas,  being  .706,  causes  it  to  rise.  The 
egg-clusters  were  placed  on  a  small  card-board  stand  which 
reached  nearly  to  the  top  of  the  hood,  which  was  punctured 
several  times,  so  that  the  gas  might  readily  pass  through. 
Forty  cubic  centimeters  of  sulphuric  acid  were  then  added 
to  one-half  ounce  of  potassic  cyanide,  the  gas  being  passed 
under  the  hood.  No  change  was  visible  in  the  eggs  after 
this  treatment,  and  nearly  all  of  them  hatched.  January  12. 
Five  egg-clusters  were  treated  with  hydrocyanic  acid  gas, 
under  a  hood  made  of  wet  unbleached  cotton,  the  cloth  being 
drawn  closely  to  the  table  and  weighted  down,  so  that  no  air 
could  pass  under  the  hood ;  with  this  exception,  the  process 
and  conditions  were  the  same  as  in  the  preceding  experi- 
ment. Nearly  all  of  the  eggs  hatched  after  being  subjected 
to  this  treatment.  January  12.  Ten  egg-clusters  were 
treated  with  pure,  concentrated  hydrocyanic  acid  gas  for 
one  hour.  The  apparatus  consisted  of  three  four-ounce 
Florence  flasks,  marked  A,  B  and  C.  Flask  A  contained 
about  one-half  an  ounce  of  potassic  cyanide,  B  contained 
concentrated  sulphuric  acid,  and  C  the  ten  egg-clusters.  A 
was  connected  with  B  by  means  of  a  tube  which  dipped 
below  the  surface  of  the  sulphuric  acid  in  B.  The  escape 
tube  from  B  passed  through  the  stopper  of  C.  There  was 


412  THE   GYPSY   MOTH. 

also  a  small  escape  tube  for  the  air  to  pass  out.  Sulphuric 
acid  was  added  to  the  potassic  cyanide  in  flask  A,  and  the 
hydrocyanic  acid  gas  passed  through  the  sulphuric  acid  in 
B,  which  thoroughly  dried  it ;  it  then  passed  out  into  C. 
After  the  air  had  all  passed  out  of  C,  the  escape  tube  was 
stopped.  The  gas  was  generated  for  an  hour,  after  which 
time  an  examination  of  the  eggs  showed  no  change,  and 
nearly  all  of  them  subsequently  hatched.  A  duplicate  ex- 
periment gave  similar  results.  January  13.  Five  egg- 
clusters  were  treated  with  pure,  concentrated  hydrocyanic 
acid  gas  for  one  hour  and  a  half.  None  of  the  eggs  hatched. 
January  13.  Five  egg-clusters  were  treated  for  two  hours 
with  hydrocyanic  acid  gas  under  a  hood.  An  examination 
of  the  eggs,  made  January  14,  showed  them  to  be  slightly 
dried,  but,  by  March  24,  about  eight-tenths  of  the  eggs  had 
hatched.  January  15.  Five  egg-clusters  were  treated  with 
hydrocyanic  acid  gas  for  fifteen  minutes.  The  eggs  did  not 
appear  to  be  affected,  although  none  of  them  hatched. 

Hydrogen  Arsenide. — April  7.  Five  egg-clusters  were 
treated  for  fifteen  minutes  with  hydrogen  arsenide,  made  by 
pouring  a  solution  of  arsenic  into  a  mixture  of  granulated 
zinc  and  hydrochloric  acid.  None  of  these  eggs  hatched. 
November  5.  A  number  of  egg-clusters  were  treated  for 
one  hour  with  hydrogen  arsenide.  None  of  the  eggs 
hatched.  February  6.  About  twenty-five  broken  egg-clus- 
ters were  treated  with  hydrogen  arsenide  for  forty-five 
minutes.  The  gas  was  made  as  follows :  A  solution  of 
arsenic  was  poured  into  a  mixture  of  hydrochloric  acid  and 
zinc.  The  gas  which  was  given  off  was  dried  by  passing 
through  a  U  tube  containing  calcium  chloride,  then  into  the 
bottle  containing  the  eggs.  None  hatched.  Several  other 
experiments  with  this  gas  gave  similar  results. 

Hydrogen  Sulphide.  — April  7.  Some  egg-clusters  were 
submitted  to  the  action  of  hydrogen  sulphide  for  ten 
minutes.  At  the  end  of  this  time  the  eggs  were  shrivelled 
and  none  hatched.  January  30.  Several  egg-clusters  were 
treated  for  one  hour  with  hydrogen  sulphide  gas,  which  was 
made  by  adding  dilute  sulphuric  acid  to  iron  sulphide.  It 
was  passed  through  a  U  tube  and  then  into  a  bottle  con- 


PLATE  64.      Pine  and  other  trees  attacked  by  the  gypsy  moth 
caterpillars  at  Lexington. 


INSECTICIDES.  413 

taining  the  egg-clusters.  None  hatched.  Februarys.  Ten 
egg-clusters  were  treated  with  hydrogen  sulphide  for  one 
hour.  None  hatched.  April  12.  Some  broken  egg-clus- 
ters were  treated,  in  an  open  bottle,  for  two  hours,  with 
hydrogen  sulphide.  None  of  them  hatched. 

Hydrochloric,  Acid  Gas. — March  31.  Some  egg-clusters 
were  submitted  for  fifteen  minutes  to  the  action  of  hydro- 
chloric acid  gas,  formed  by  adding  sulphuric  acid  to  salt. 
This  destroyed  the  eggs  by  drying  them  up.  Several  egg- 
clusters  were  submitted  to  the  action  of  hydrochloric  acid 
gas  for  thirty  minutes.  None  hatched. 

<  <  Infernal "  Mixture.  —  February  17.  A  number  of  new 
egg-clusters  were  treated  with  a  gas  made  by  adding  fifty 
per  cent,  of  sulphuric  acid  to  fifty  per  cent  of  turpentine. 
They  were  left  exposed  to  the  action  of  the  gas  over  night, 
which  destroyed  them  so  that  none  hatched.  February  19. 
Five  egg-clusters  were  treated  for  two  hours  with  this  gas. 
The  eggs  were  bleached  a  little,  and  none  hatched.  Febru- 
ary 22.  Five  egg-clusters  were  subjected  for  five  hours  to 
the  action  of  the  above-mentioned  gas.  The  eggs  were 
stained  red,  and  shrivelled  so  that  none  hatched.  February 
22.  Five  egg-clusters  were  submitted  for  ten  hours  to  the 
action  of  this  gas,  which  entirely  destroyed  the  eggs.  Eggs 
exposed  to  the  action  of  this  gas  on  February  19,  for  a 
period  of  thirty  minutes,  were  uninjured,  and  hatched  on 
March  24. 

Nitrogen  Dioxide. — March  31.  Several  egg-clusters 
were  submitted  to  nitrogen  dioxide  for  fifteen  minutes.  The 
gas  was  formed  by  adding  sulphuric  acid  to  salt  and  nitre. 
The  eggs  were  entirely  destroyed.  April  1.  A  number  of 
egg-clusters  were  submitted  for  five  minutes  to  the  action 
of  nitrogen  dioxide.  The  eggs  were  entirely  destroyed. 
August  24.  Eggs  were  treated  with  nitrous  dioxide  in  a 
hollow  tree.  The  gas  was  generated  as  in  the  preceding 
experiments.  After  this  treatment  the  eggs  were  taken  into 
a  warm  room,  where  they  began  to  hatch  on  February  31. 

Potassic  Cyanide. — March  15.  A  solution  of  potassic 
cyanide  in  water,  fifty  per  cent.,  and  of  alcohol,  fifty  per 
cent.,  was  dropped  upon  five  egg-clusters,  which  it  pene- 


414  THE   GYPSY   MOTH. 

trated  readily,  but  did  not  affect  the  vitality  of  the  eggs. 
March  15.  Several  egg-clusters  were  treated  in  the  same 
manner  as  in  the  preceding  experiment,  and  about  one-tenth 
of  the  eggs  hatched. 

Pine  Tar  Mixtures. — February  1.  A  mixture,  com- 
posed of  fifty  per  cent,  of  pine  tar  and  fifty  per  cent,  of 
phenol,  was  poured  upon  five  egg-clusters.  It  soaked  into 
the  clusters  readily,  and  blackened  them,  apparently  de- 
stroying the  eggs.  February  3.  A  mixture  of  pine  tar, 
fifty  per  cent.,  and  turpentine,  fifty  per  cent.,  was  dropped 
upon  five  egg-clusters.  It  penetrated  readily,  turning  the 
eggs  black  and  apparently  destroying  them.  February  3. 
A  mixture  containing  equal  parts  of  pine  tar,  phenol  and 
turpentine  was  dropped  upon  five  egg-clusters,  completely 
destroying  the  eggs.  A  mixture  composed  of  forty  per 
cent,  of  pine  tar,  forty  per  cent,  of  phenol,  twenty  per  cent, 
of  alcohol,  with  corrosive  sublimate,  was  dropped  upon  ten 
egg-clusters,  and,  although  the  eggs  did  not  appear  to  be 
destroyed,  none  hatched.  March  6.  A  mixture  of  pine 
tar,  fifty  per  cent.,  alcohol,  forty-five  per  cent.,  tannic  acid, 
two  and  one-half  per  cent.,  and  ferrous  sulphate,  two  and 
one-half  per  cent.,  was  dropped  upon  a  number  of  egg- 
clusters,  which  it  readily  penetrated,  rendering  the  eggs  soft. 
The  object  of  the  last  two  substances  was  to  give  the  solu- 
tion a  black  color.  March  6.  A  mixture  of  pine  tar,  fifty 
per  cent.,  alcohol,  forty-five  per  cent.,  and  Stafford's  ink, 
five  per  cent.,  was  dropped  upon  some  egg-clusters.  It 
readily  penetrated  to  the  bottom  layer,  destroying  the 


Phenol.  — January  21.  A  small  amount  of  liquid  phenol 
was  poured  upon  an  egg-cluster.  This  burned  the  eggs  to 
a  crisp.  January  21.  Five  egg-clusters  were  treated  for 
ten  minutes  with  vapors  of  phenol,  one  hundred  per  cent., 
care  being  taken  that  the  egg-clusters  should  be  dampened 
by  the  vapors.  The  eggs  were  badly  burned.  January  21. 
Five  egg-clusters  were  treated  for  fifteen  minutes  in  the 
same  manner  as  in  the  preceding  experiment,  except  that 
the  vapors  were  not  allowed  to  wet  the  egg-clusters.  Ap- 
parently the  eggs  were  not  injured,  for,  by  March  24,  nearly 


INSECTICIDES.  415 

all  had  hatched.  January  25.  A  mixture  of  phenol,  ten 
per  cent.,  and  alcohol,  ninety  per  cent.,  was  poured  upon 
five  egg-clusters,  which  were  blackened  and  burned.  Jan- 
uary 25.  Five  egg-clusters  were  treated  with  a  mixture  of 
phenol,  twenty  per  cent.,  and  water,  eighty  per  cent.  This 
mixture  was  stirred  until  it  became  milky  white,  then  a  little 
was  poured  upon  the  egg-clusters,  and  seriously  burned 
them.  January  30.  A  mixture  of  phenol,  four  per  cent., 
and  water,  ninety-six  per  cent.,  was  poured  upon  five  egg- 
clusters.  The  mixture  penetrated  only  a  part  of  the  egg- 
cluster,  and  nearly  one-half  of  the  eggs  hatched.  January 
30.  A  mixture  of  phenol,  three  per  cent.,  and  water, 
ninety-seven  per  cent.,  was  poured  upon  five  egg-clusters. 
About  nine-tenths  of  the  eggs  hatched.  February  1.  A 
mixture  composed  of  phenol,  fifty  per  cent.,  and  sulphuric 
acid,  fifty  per  cent.,  was  dropped  upon  five  egg-clusters. 
This  mixture  slowly  penetrated  the  egg-clusters  and  de- 
stroyed the  eggs.  February  2.  A  mixture  containing  fifty 
per  cent,  alcohol,  twenty-five  per  cent,  phenol  and  twenty- 
five  per  cent,  of  sulphuric  acid,  was  dropped  upon  five  egg- 
clusters,  destroying  the  eggs.  February  26.  A  mixture 
of  fifty  per  cent,  alcohol,  twenty-five  per  cent,  phenol, 
twenty-five  per  cent,  sulphuric  acid,  with  a  little  potassic 
ferricyanide  and  ferrous  chloride,  was  dropped  upon  some 
egg-clusters.  The  mixture  readily  penetrated  the  clusters, 
turning  them  dark  blue  and  completely  destroying  the  eggs. 
February  2.  A  mixture  of  alcohol,  fifty  per  cent.,  phenol, 
twenty-five  per  cent.,  and  sulphuric  acid,  twenty-five  per 
cent.,  was  dropped  upon  five  egg-clusters.  It  readily  pene- 
trated the  clusters,  turning  them  black  and  completely  de- 
stroying the  eggs.  February  25.  A  mixture  of  alcohol, 
sixty  per  cent.,  phenol,  twenty  per  cent.,  and  sulphuric 
acid,  twenty  per  cent.,  was  dropped  upon  some  egg-clusters, 
turning  them  black  and  completely  destroying  the  eggs. 
March  1.  A  mixture  of  phenol,  fifty  per  cent.,  turpentine 
and  nitric  acid,  fifty  per  cent.,  was  dropped  upon  some 
egg-clusters,  entirely  destroying  the  eggs.  March  14.  A 
mixture  composed  of  phenol,  fifty  per  cent.,  turpentine  with 
a  small  amount  of  concentrated  nitric  acid,  fifty  per  cent., 


416  THE   GYPSY  MOTH. 

was  dropped  upon  some  egg-clusters,  entirely  destroying 
the  eggs. 

Pyroligenous  Acid. — February  10.  Eight  egg-clusters 
were  moistened  with  pyroligenous  acid,  but  it  would  not 
penetrate  the  clusters. 

Spruce  Gum. — Twenty  per  cent,  of  spruce  gum,  thirty- 
five  per  cent,  of  rosin,  thirty-five  per  cent,  of  cotton-seed 
oil,  five  per  cent,  of  turpentine  and  five  per  cent,  of  pine 
tar  were  melted  and  mixed  together,  and  some  egg-clusters 
saturated  with  the  solution.  None  of  the  eggs  hatched. 

Sulphur  Di-oxide. — January  25.  Five  egg-clusters 
were  placed  in  a  tight  box  and  submitted  for  ten  minutes  to 
the  fumes  of  burning  sulphur.  March  24,  about  three-fifths 
of  the  eggs  had  hatched.  January  25.  Five  egg-clusters, 
placed  in  a  tight  wooden  box,  were  submitted  for  twenty 
minutes  to  the  fumes  of  burning  sulphur.  March  24,  nearly 
all  of  the  eggs  had  hatched. 

Turpentine.  —  A  quantity  of  turpentine  was  poured  on 
five  egg-clusters.  It  readily  penetrated,  but  apparently  did 
not  affect  the  eggs,  as  nearly  all  of  them  hatched. 

During  the  month  of  October,  1893,  Mr.  C.  W.  Minott 
experimented  in  the  field  with  a  number  of  mixtures  having 
creosote  oil  as  a  basis.  All  of  these  mixtures  were  effective 
in  destroying  the  eggs  of  the  gypsy  moth.  The  lowest  per 
cent,  of  creosote  oil  used  was  in  a  mixture  composed  of 
eighty  per  cent,  of  turpentine  and  twenty  per  cent,  of  creo- 
sote oil.  Even  when  diluted  to  this  degree,  it  was  found  to 
be  effective. 

The  following  experiments  on  the  eggs  of  the  gypsy  moth 
were  conducted  by  Mr.  Kirkland,  in  1895  :  — 

Kerosene.  — January  5.  Twelve  egg-clusters  were  treated 
with  kerosene  oil ;  these  hatched  April  20.  April  25.  Five 
egg-clusters  treated  with  kerosene  oil ;  hatched  May  1 . 

Turpentine. — January  5.  Ten  egg-clusters  treated  with 
turpentine;  hatched  April  18. 

Kerosene  and  Turpentine. — May  2.  Egg-clusters  which 
had  commenced  hatching  were  soaked  in  a  mixture  com- 
posed of  equal  parts  of  kerosene  and  turpentine.  May  6. 


INSECTICIDES.  417 

Six  eggs-clusters  re-commenced  hatching,  and  a  few  cater- 
pillars emerged. 

Crude  Castor  Oil  and  Turpentine. — January  5.  Five 
egg-clusters,  treated  with  the  above  mixture,  hatched  April 
30. 

Paraffins  Gas  or  Residuum  Oil. — Thinking  this  oil  might 
be  of  some  value  for  treating  egg-clusters,  a  number  of 
experiments  were  made  which  gave  very  satisfactory  re- 
sults. January  5.  Twelve  egg-clusters  were  treated  with 
paraffine  gas  oil,  none  of  which  hatched.  During  the  winter 
and  spring  of  1895,  from  one  hundred  to  two  hundred  egg- 
clusters  were  treated  with  paraffine  gas  oil,  with  the  result 
that  none  of  them  hatched. 

Raupenleim. — April  27.  Five  egg-clusters  were  care- 
fully covered  with  Raupenleim,  the  layer  being  about  one- 
eighth  of  an  inch  thick.  None  of  the  eggs  hatched. 

The  experiments  in  treating  egg-clusters  with  various 
gases  were  made  with  a  view  to  finding  some  practical  way 
of  dealing  with  stone  walls,  hollow  trees  and  other  more  or 
less  inaccessible  places,  in  which  eggs  had  been  laid  in 
large  quantities.  The  substances  which  were  found  to  give 
the  most  satisfactory  results,  i.  e.,  chlorine  and  bromine 
vapors,  were  tested  on  a  large  scale  in  the  field,  but  here 
their  use  was  found  to  be,  at  best,  only  partially  effective. 

INSECTICIDES  FOR  DESTROYING  THE  CATERPILLARS. 
Spraying  with  the  common  arsenical  poisons,  such  as 
Paris  green,  London  purple,  etc.,  was  one  of  the  first 
methods  employed  for  the  destruction  of  the  caterpillars 
of  the  gypsy  moth,  and  the  failure  of  these  poisons  to  do 
effective  work  in  the  field  has  already  been  stated.  When 
it  became  evident  that  the  caterpillars  were  not  being  de- 
stroyed in  any  great  numbers  by  these  poisons,  an  effort 
was  made  to  discover  a  more  effective  poison,  and  much 
time  and  labor  were  spent  in  this  undertaking.  The  most 
careful  attention  was  given  to  this  problem;  for,  with 
modern  spraying  machinery,  the  thorough  application  of 
a  poison  to  trees  is  easily  accomplished,  and  thus  a  cheap, 


418  THE   GYPSY   MOTH. 

practical  and  effective  method  of  destroying  the  caterpillars 
of  the  gypsy  moth  would  be  provided  if  a  poison  could  be 
found  which  would  meet  the  exigencies  of  the  case.  It  will 
be  seen  by  the  records  which  follow  that  we  have  experi- 
mented with  insecticides  in  general  use,  which  are  adapted 
to  our  work,  and  also  with  many  new  insecticides  which 
were  prepared  for  this  purpose  by  our  former  chemist, 
Mr.  F.  C.  Moulton. 

All  of  the  insecticide  experiments  here  recorded  were 
performed  under  my  immediate  supervision,  by  Messrs. 
Reid  and  Schrader  in  1893,  Messrs.  Minott,  Mosher  and 
Kirkland  in  1894,  and  by  Mr.  Kirkland  and  his  assistants 
in  1895. 

Details  of  the  Experiments. 

The  caterpillars  used  in  the  field  or  out-door  experiments 
were  taken  from  infested  trees  near  the  place  of  experi- 
mentation. Those  used  in  the  in-door  experiments  were, 
as  a  rule,  from  eggs  hatched  early  in  the  season  by  means 
of  artificial  heat. 

In  the  in-door  experiments  on  young  caterpillars  lettuce 
was  the  food  plant  generally  used,  leaves  of  elm,  apple  or 
willow  being  substituted  as  soon  as  such  foliage  could  be 
obtained.  In  the  field  experiments  the  caterpillars  were 
confined  upon  branches  of  trees  on  which  they  were  known 
to  feed  readily. 

All  poisons  used  in  the  experiments  of  1893,  and  the 
greater  part  of  those  used  in  1894,  were  carefully  weighed 
out  in  the  insectary  at  Amherst.  During  the  latter  part 
of  1894,  and  throughout  the  season  of  1895,  they  were 
weighed  on  a  very  accurate  set  of  balances  at  the  Maiden 
office. 

The  poison  was  applied  to  the  foliage  used  in  the  in-door 
experiments  both  by  dipping  the  leaves  in  the  poison  mixt- 
ures and  by  spraying  with  small  hand  bellows.  In  the 
field  experiments  the  poison  was  always  applied  by  use  of 
the  spraying  bellows.  After  heavy  rains  the  branches  on 
which  the  caterpillars  were  confined  were  resprayed  in  the 
same  manner  as  would  be  adopted  in  spraying  operations 
in  the  field.  In  nearly  all  cases  a  small  amount  of  glucose 


INSECTICIDES.  419 

was  added  to  the  poison  mixtures,  in  order  to  increase  the 
adhesive  qualities.  In  the  experiments  conducted  at  the 
insectary  the  caterpillars  were  confined  in  glass  jars  or  in 
lantern  globes.  In  the  field  experiments  the  caterpillars 
were  sacked  in  (enclosed  by  means  of  a  thin  cloth  bag  of 
proper  dimensions)  upon  the  branches  of  trees.  In  the  case 
of  the  in-door  experiments  the  poisoned  food  was  renewed 
and  the  jars  cleaned  daily.  For  the  field  experiments 
branches  of  sufficient  size  to  allow  the  caterpillars  to  feed 
till  reaching  maturity  were  chosen,  and  thus,  as  a  rule,  no 
change  was  necessary. 

Each  jar  or  sack  used  in  the  experiments  was  given  a 
number,  which  was  recorded  in  a  book,  in  which  the  records 
of  the  ten  caterpillars  used  in  each  experiment  were  carefully 
noted.  In  many  of  the  experiments  a  ' '  check  "  was  em- 
ployed, to  determine  the  normal  death  rate  of  caterpillars 
feeding  on  unpoisoned  food.  This  check  consisted  of  the 
same  number  of  caterpillars  confined  in  a  jar  or  bag  in  the 
same  manner  as  those  in  the  experiment,  with  the  exception 
that  they  were  kept  supplied  with  fresh,  unpoisoned  food. 

Daily  observations  were  made  both  upon  caterpillars  feed- 
ing on  the  poisoned  and  unpoisoned  food,  and  the  results 
recorded.  Many  of  the  experiments  on  young  caterpillars 
were  discontinued  at  the  end  of  about  a  fortnight,  or  after 
they  had  entered  the  succeeding  molt. 

The  following  pages  contain  the  records  of  the  experi- 
ments which  have  been  conducted  with  the  different  insecti- 
cides :  — 

Experiments  with  Paris  Green. 
i  Ib.  Paris  Green  to  150  gal.  Water. 

No.  1.  — March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  £  Ib.  to  150  gal.  of 
water.  Two  died  on  the  third,  three  the  fourth,  one  the 
fifth,  three  the  sixth  and  one  the  seventh  day. 

Check  experiment :  none  dead. 

No.  2.  —April  26,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green,  in  the  proportion  of  £  Ib.  to  150  gal.  of  water. 


420  THE   GYPSY   MOTH. 

Three  died  the  second,  three  the  third,  one  the  fourth  and 
one  the  fifth  day,  and  two  escaped. 

Check  experiment :  none  dead. 

No.  3.— May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  £  Ib.  to  150  gal.  of 
water.  Two  died  the  third,  one  the  fourth,  three  the  sixth, 
two  the  seventh  and  two  the  eighth  day. 

Check  experiment :  one  died  the  third  day. 

No.  4.  —  June  10,  1894.  Ten  caterpillars  of  the  second 
molt  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  £  Ib.  to  150  gal.  of 
water.  One  died  on  the  seventh,  two  the  eighth,  five  the 
ninth  and  two  the  tenth  day. 

Check  experiment :  none  dead. 

No.  5. — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  £  Ib.  to  150  gal.  of 
water.  One  died  the  fourth,  two  the  fifth,  two  the  sixth, 
two  the  seventh,  one  the  eighth,  one  the  ninth  and  one  the 
eleventh  day. 

Check  experiment :  none  dead. 

No.  6.  —  June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  £  Ib.  to  150  gal.  of 
water.  Three  died  the  third,  two  the  fourth,  one  the  fifth, 
one  the  sixth  and  three  the  seventh  day. 

Check  experiment :  one  died  the  fifth  and  one  the  sixth 
day. 

No.  7  (field  experiment). — June  28,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  Paris  green,  in  the  pro- 
portion of  £  Ib.  to  150  gal.  of  water,  and  ten  fourth-molt 
caterpillars  placed  upon  it.  July  5,  the  foliage  was  so  badly 
burned  that  the  caterpillars  were  removed  to  an  unsprayed 
branch.  July  30,  the  food  supply  having  given  out,  they 
were  again  removed  to  another  unsprayed  branch.  Five 
of  these  caterpillars  died  before  pupating,  and,  of  the  five 
that  began  to  pupate,  three  emerged.  Foliage  very  badly 
burned. 


INSECTICIDES.  421 

No.  8  (field  experiment).— June  28,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  Paris  green,  in  the  pro- 
portion of  £  Ib.  to  150  gal.  of  water,  and  six  fourth-molt 
caterpillars  placed  upon  it.  July  5,  the  foliage  was  so  badly 
burned  that  the  caterpillars  were  transferred  to  a  freshly 
sprayed  oak  branch.  July  19,  the  branch  was  resprayed 
on  account  of  heavy  rains.  Of  the  six  caterpillars,  only 
two,  and  possibly  one  of  these  was  injured,  died  before 
pupating.  Of  the  four  that  pupated,  two  emerged.  The 
foliage  of  the  hop-hornbeam  was  very  badly  burned,  while 
that  of  the  oak  was  in  good  condition. 

No.  9.— July  10,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  £  Ib.  to  150  gal.  of 
water.  One  died  the  third  day ;  one  pupated  the  fourth, 
three  the  seventh  and  three  the  eighth  day ;  two  died  the 
eleventh  day. 

Check  experiment:  three  pupated  the  fourth  day;  one 
died  the  seventh  and  one  the  eighth  day. 

No.  10  (field  experiment).— July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green,  in  the  proportion 
of  £  Ib.  to  150  gal.  of  water.  One  died  the  eighth  and  one 
the  eleventh  day ;  one  pupated  the  thirteenth  day ;  one  died 
and  two  pupated  the  fourteenth  day ;  one  pupated  the  twen- 
tieth, one  the  twenty-third,  one  the  twenty-eighth  and  one 
the  twenty-ninth  day. 

No.  11  (field  experiment). — June  28,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  Paris  green,  in  the  pro- 
portion of  £  Ib.  to  150  gal.  of  water,  and  ten  caterpillars,  of 
the  fifth  molt,  placed  upon  it.  July  5,  the  foliage  was  so 
badly  burned  that  the  caterpillars  were  transferred  to  a 
freshly  sprayed  branch  of  oak.  On  the  15th  of  July,  for 
lack  of  food,  they  were  again  removed  to  another  branch  of 
oak  which  had  also  been  sprayed.  Only  one  caterpillar 
died  before  pupating,  and  that  one  lived  twenty-four  days 
after  the  first  spraying.  Of  the  nine  that  pupated,  five 
emerged.  The  foliage  of  the  hop-hornbeam  was  very  badly 
burned,  while  that  of  the  oak  was  only  slightly  so,  if  at  all. 


422  THE  GYPSY  MOTH. 

No.  12  (field  experiment). — June  28,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  Paris  green,  in  the  pro- 
portion of  £  Ib.  to  150  gal.  of  water,  and  ten  fifth-molt 
caterpillars  placed  upon  it.  July  5,  the  foliage  was  so  badly 
burned  that  the  caterpillars  were  removed  to  another  branch 
of  hop-hornbeam  which  was  not  sprayed.  July  11,  the 
foliage  having  been  entirely  stripped  from  the  branch,  they 
were  again  removed  to  another  unsprayed  branch.  Of  these 
caterpillars,  none  died  before  pupating,  and  four  of  them 
completed  the  process  of  pupation  and  emerged.  Foliage 
very  badly  burned. 

f  Ib.  Paris  Green  to  150  gal  Water. 

No.  13. —April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  }  Ib.  to  150  gal.  of 
Avater.  Four  died  the  second,  five  the  third  and  one  the 
fourth  day. 

Check  experiment :  none  dead. 

No.  14. — May  9,,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green,  in  the  proportion  of  f  Ib.  to  150  gal.  of  water. 
Three  died  the  second,  four  the  third,  two  the  fifth  and  one 
the  sixth  day. 

Check  experiment :  none  dead. 

No.  15. — May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  ^  Ib.  to  150  gal.  of 
water.  One  died  the  fourth,  one  the  fifth,  one  the  sixth, 
one  the  seventh,  three  the  eighth  and  three  the  ninth  day. 

Check  experiment :  none  dead. 

No.  16.  —  June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  f  11).  to  150  gal.  of 
water.  One  died  the  fifth,  one  the  seventh,  three  the  ejghth, 
two  the  ninth  and  three  the  eleventh  day. 

Check  experiment :  none  dead. 

No.  17.  — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 


INSECTICIDES.  423 

with  Paris  green,  in  the  proportion  of  |  Ib.  to  150  gal.  of 
water.  One  died  the  second,  three  the  third,  three  the  fifth, 
three  the  sixth  and  one  the  seventh  day. 

Check  experiment :  one  accidentally  killed  the  seventh 
day. 

No.  18.  —June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  £  Ib.  to  150  gal.  of 
water.  Two  died  the  second,  three  the  third,  three  the  fifth 
and  two  the  sixth  day. 

Check  experiment :  one  pupated  the  third  and  one  died 
the  fourth  day. 

No.  19  (field  experiment). — June  27,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  Paris  green,  in  the  pro- 
portion of  |  Ib.  to  150  gal.  of  water,  and  six  fourth-molt 
caterpillars  placed  upon  it.  July  8,  the  foliage  was  so 
badly  burned  that  the  leaves  fell  off,  and  the  caterpillars 
were  removed  to  another  branch  which  had  not  been  sprayed. 
By  August  12,  all  of  the  caterpillars  were  dead,  with  the 
exception  of  one  which  pupated  and  emerged. 

No.  20  (field  experiment).— June  27,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  Paris  green,  in  the  pro- 
portion of  |  Ib.  to  150  gal.  of  water,  and  ten  fourth-molt 
caterpillars  were  placed  upon  it.  July  8,  one  caterpillar 
had  died  and  the  foliage  had  become  badly  burned.  The 
remaining  caterpillars  were  transferred  to  a  freshly  sprayed 
oak  branch.  July  19,  all  the  caterpillars  were  dead.  Foli- 
age slightly  burned. 

No.  21. — July  10,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  ^  Ib.  to  150  gal.  of 
water.  One  died  the  second  and  one  the  third  day ;  two 
died  and  one  pupated  the  fourth  day ;  two  died  and  one 
pupated  the  sixth  day ;  one  died  the  eleventh  and  one  the 
twelfth  day. 

Check  experiment :  one  pupated  the  third  day ;  one  died 
the  fourth  day ;  one  pupated  the  sixth,  two  the  eighth,  one 
the  ninth  and  one  the  eleventh  day. 

No.  22  (field  experiment). — July  7,  1894.     Ten    cater- 


424  THE   GYPSY  MOTH. 

pillars,  of  the  fifth  molt,  we're  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green,  in  the  proportion 
of  ^  Ib.  to  150  gal.  of  water.  Two  died  and  one  pupated 
the  seventh  day ;  two  pupated  the  fourteenth,  two  the  six- 
teenth, one  the  nineteenth,  one  the  twenty-first  and  one  the 
twenty-third  day. 

No.  23  (field  experiment) .— June  27,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  Paris  green,  in  the  pro- 
portion of  |  Ib.  to  150  gal.  of  water,  and  ten  fifth-molt 
caterpillars  placed  upon  it.  July  8,  one  died,  and  the  food 
having  given  out,  those  remaining  were  transferred  to  an- 
other branch.  Of  these,  six  pupated  and  emerged,  while 
the  other  three  pupated,  but  died  without  emerging.  The 
foliage  which  was  sprayed  was  so  badly  burned  that  the 
leaves  curled  and  fell  olf. 

No.  24  (field  experiment) .— June  27,  1894.  A  branch 
of  hop-hornbeam  was  sprayed  with  Paris  green,  in  the  pro- 
portion of  £  Ib.  to  150  gal.  of  water,  and  nine  fifth-molt 
caterpillars  placed  upon  it.  July  8,  two  having  died,  the 
remaining  caterpillars  were  transferred  to  a  freshly  sprayed 
oak  branch,  as  the  foliage  of  the  hop-hornbeam  was  burned 
to  a  crisp.  By  the  4th  of  August  all  the  caterpillars  were 
dead.  While  the  foliage  of  the  hop-hornbeam  was  badly 
burned,  that  of  the  oak  remained  in  good  condition. 

1  Ib.  Paris  Green  to  150  gal.  Water. 

No.  26.  — April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  1  Ib.  to  150  gal.  of 
water.  Two  died  the  first,  five  the  third  and  one  the  fourth 
day ;  two  escaped. 

Check  experiment :  none  dead. 

No.  27. — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green,  in  the  proportion  of  1  Ib.  to  150  gal.  of  water. 
One  died  the  first,  two  the  second,  five  the  third,  one  the 
fourth  and  one  the  fifth  day. 

Check  experiment :  none  dead. 

No.  28. — May  28,  1894.     Ten  caterpillars,  of  the  first 


INSECTICIDES.  425 

molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  1  Ib.  to  150  gal.  of 
water.  Three  died  the  third,  one  the  fourth,  one  the  fifth, 
four  the  sixth  and  one  the  seventh  day. 

Check  experiment :  one  dead. 

No.  29.  — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  1  Ib.  to  150  gal.  of 
water.  One  died  the  second,  one  the  third,  two  the  fourth, 
one  the  fifth,  four  the  seventh  and  one  the  eighth  day. 

Check  experiment :  none  dead. 

No.  30.— June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  1  Ib.  to  150  gal.  of 
water.  Two  died  the  second,  three  the  third,  two  the 
fourth,  one  the  sixth  and  two  the  seventh  day. 

Check  experiment :  none  dead. 

No.  31.— June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  1  Ib.  to  150  gal.  of 
water.  Four  died  the  third,  one  the  fourth,  one  the  fifth, 
two  the  sixth,  one  the  seventh  and  one  the  eighth  day. 

Check  experiment :  one  died  the  fifth  day ;  one  pupated 
and  one  died  the  sixth  day. 

No.  32  (field  experiment). — June  26,  1893.  A  branch 
of  apple  tree  was  sprayed  with  Paris  green,  in  the  propor- 
tion of  1  Ib.  to  150  gal.  of  water,  and  ten  fourth-molt  cater- 
pillars placed  upon  it.  Of  these,  four  died  without  pupating, 
and,  of  the  six  which  began  to  pupate,  none  emerged. 
Foliage  slightly  burned. 

No.  33  (field  experiment). — June  26,  1893.  An  apple- 
tree  branch  was  sprayed  with  Paris  green,  in  the  proportion 
of  1  Ib.  to  150  gal.  of  water,  and  nine  fourth-molt  cater- 
pillars placed  upon  it.  July  16,  the  branch  having  been 
broken  off  by  the  wind,  the  caterpillars  were  transferred  to 
another  tree,  and  the  branch  sprayed.  Five  died  before 
pupating,  and,  of  the  four  which  pupated,  two  emerged. 
Foliage  badly  burned. 

No.  34.  — July  10,  1894.     Ten  caterpillars,  of  the  fifth 


426  THE   GYPSY  MOTH. 

molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  1  Ib.  to  150  gal.  of 
water.  One  died  the  fourth  day ;  three  died  and  one  pu- 
pated the  sixth  day ;  two  died  the  ninth,  one  the  tenth,  one 
the  eleventh  and  one  the  twelfth  day. 

Check  experiment :  one  died  the  second  day ;  two  pupated 
the  sixth,  one  the  seventh,  one  the  ninth  and  one  the  tenth 
day. 

No.  35  (field  experiment). — July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green,  in  the  proportion 
of  1  Ib.  to  150  gal.  of  water.  Two  pupated  the  fourteenth, 
two  the  sixteenth  and  three  the  eighteenth  day ;  one  died 
the  nineteenth  and  two  pupated  the  twentieth  day. 

No.  36  (field  experiment). — June  26,  1893.  A  branch 
of  apple  tree  was  sprayed  with  Paris  green,  in  the  propor- 
tion of  1  Ib.  to  150  gal.  of  water,  and  ten  fifth-molt  cater- 
pillars were  placed  upon  it.  Of  these,  six  died  before  pu- 
pating ;  four  pupated,  three  of  which  emerged.  For  some 
reason  the  foliage  appeared  to  be  quite  badly  burned, 
although  the  Paris  green  was  in  the  proportion  commonly 
used  for  spraying. 

No.  37  (field  experiment). — June  26,  1893.  A  branch 
of  apple  tree  was  sprayed  with  Paris  green,  in  the  propor- 
tion of  1  Ib.  to  150  gal.  of  water,  and  ten  fifth-molt  cater- 
pillars placed  upon  it.  In  this  experiment  the  poison  took 
effect  more  quickly  than  in  the  corresponding  experiments, 
all  of  the  caterpillars  having  died  within  three  weeks". 

No.  38  (field  experiment) .— July  12,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  Paris  green,  in  the  pro- 
portion of  1  Ib.  to  150  gal.  of  water,  and  ten  caterpillars  of 
the  fifth  molt  placed  upon  the  branch.  July  21,  the  foliage 
was  so  badly  burned  that  the  caterpillars  were  transferred 
to  a  freshly  sprayed  branch  of  oak,  which  was  resprayed 
July  27,  on  account  of  the  rain.  Four  caterpillars  pupated, 
two  of  which  emerged.  Foliage  of  the  hop-hornbeam  very 
badly  burned ;  that  of  the  oak  burned  somewhat  less. 

No.  39  (field  experiment).  — July  12,  1893.  Paris  green, 
in  the  proportion  of  1  Ib.  to  150  gal.  of  water,  was  allowed 


INSECTICIDES.  427 

to  stand  for  nearly  three  hours,  to  determine  the  difference 
in  action  between  this  and  the  experiments  where  the  poison 
had  not  been  allowed  to  stand.  An  oak  branch  was  sprayed 
with  this  mixture,  and  ten  large  fifth-molt  caterpillars 
placed  upon  it.  July  21,  the  branch  was  resprayed  on 
account  of  heavy  rain,  and  on  July  25  the  foliage  became  so 
badly  burned  that  the  caterpillars  were  transferred  to  a 
freshly  sprayed  oak  branch.  Seven  of  the  ten  began  to 
pupate,  but  of  these  only  two  emerged,  and  one  of  those 
was  imperfect.  Foliage  of  the  first  branch  was  very  badly 
burned,  while  that  of  the  second  was  in  good  condition. 

14  Ibs.  Parts  Green  to  150  gal.  Water. 

No.  40. — April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  1£  Ibs.  to  150  gal. 
of  water.  One  died  on  the  first,  one  the  second  and  six  the 
third  day  ;  two  escaped. 

Check  experiment :  none  dead. 

No.  41. — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green,  in  the  proportion  of  1£  Ibs.  to  150  gal.  of 
water.  Five  died  the  second,  three  the  third  and  two  the 
fourth  day. 

Check  experiment :  none  dead. 

No.  42.  —May  28,  1895.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  \%  Ibs.  to  150  gal.  of 
water.  Four  died  the  third,  three  the  fourth  and  three  the 
fifth  day. 

Check  experiment :  one  died  the  fourth  day. 

No.  43.  — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  1^  Ibs.  to  150  gal.  of 
water.  Two  died  the  second,  one  the  third,  one  the  fourth, 
one  the  fifth,  two  the  sixth,  two  the  seventh  and  one  the 
eighth  day. 

Check  experiment :  none  dead. 

No.  44.  —  June  21,  1894.     Ten  caterpillars,  of  the  third 


428  THE   GYPSY   MOTH. 

molt,  were  placed  on  elin  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  1£  Ibs.  to  150  gal. 
of  water.  Two  died  the  third,  two  the  fourth,  three  the 
fifth,  one  the  sixth  and  two  the  seventh  day. 

Check  experiment :  none  dead. 

No.  45.  —June  29,  1895.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  1£  Ibs.  to  150  gal. 
of  water.  Two  died  the  second,  four  the  third,  three  the 
fourth  and  one  the  fifth  da}'. 

Check  experiment :  one  died  the  fourth  day. 

No.  46  (field  experiment). — June  £6,  1893.  An  apple- 
tree  branch  was  sprayed  with  Paris  green,  in  the  proportion 
of  1£  Ibs.  to  150  gal.  of  water,  and  eight  fourth-molt  cater- 
pillars placed  upon  it.  Six  caterpillars  in  this  experiment 
died  gradually,  one  lived  over  ten  weeks  on  the  foliage  and 
pupated.  Another  lived  on  the  foliage  a  month,  then  pu- 
pated and  finally  emerged.  Foliage  somewhat  burned. 

No.  47  (field  experiment). — June  26,  1893.  An  apple- 
tree  branch  was  sprayed  with  Paris  green,  in  the  proportion 
of  1J  Ibs.  to  150  gal.  of  water,  and  ten  fourth-molt  cater- 
pillars placed  upon  it.  Of  these,  all  but  one  died  before 
beginning  to  pupate,  and  that  one  was  not  able  to  complete 
the  process.  It  took  more  than  a  week  for  the  poison  to 
begin  to  act,  and  the  last  caterpillar  lived  over  six  weeks. 
The  foliage  was  badly  burned. 

No.  48.  — July  10,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  1|-  Ibs.  to  150  gal.  of 
water.  Two  died  and  one  pupated  the  third  day  ;  one  died 
the  fourth,  two  the  sixth,  three  the  eighth  and  one  the 
twelfth  day. 

Check  experiment :  one  died  the  second  day  ;  one  pupated 
the  fourth,  one  the  fifth,  one  the  sixth  and  one  the  seventh 
day. 

No.  49  (field  experiment). — July  7,  1894.  Ten  cater-' 
pillars,  of  the  fifth  molt,  were  placed  on  a  willow  branch 
which  had  been  sprayed  with  Paris  green,  in  the  proportion 
of  1|  Ibs.  to  150  gal.  of  water.  One  died  and  one  pupated 


PLATE  65.     White  pine  and  other  trees  stripped  by  the  cater- 
pillars of  the  gypsy  moth. 


INSECTICIDES.  429 

the  seventh  day ;  one  died  the  thirteenth  day ;  one  died  and 
two  pupated  the  fourteenth  day ;  two  pupated  the  eighteenth, 
one  the  twenty-seventh  and  one  the  thirty-first  day. 

No.  50  (field  experiment). — June  26,  1893.  An  apple- 
tree  branch  was  sprayed  with  Paris  green,  in  the  proportion 
of  1£  Ibs.  to  150  gal.  of  water,  and  ten  fifth-molt  cater- 
pillars placed  upon  it.  By  the  5th  of  August  all  had  died, 
none  having  completed  the  process  of  pupation,  although 
two  or  three  had  begun.  The  foliage  was  badly  burned. 

No.  51  (field  experiment). — June  26,  1893.  An  apple- 
tree  branch  was  sprayed  with  Paris  green,  in  the  proportion 
of  1J  Ibs.  to  150  gal.  of  water,  and  ten  fifth-molt  cater- 
pillars placed  upon  it.  Of  these  caterpillars,  six  died  with- 
out pupating ;  three  began  to  pupate,  but  died  later ;  and 
one  pupated  and  emerged.  The  foliage  was  badly  burned. 

No.  52  (field  experiment). — July  14,  1893.  An  oak 
branch  was  sprayed  with  Paris  green,  in  the  proportion  of 
1£  Ibs.  to  150  gal.  of  water,  and  ten  fifth-molt  caterpillars 
placed  upon  it.  On  July  20,  the  branch  was  resprayed  on 
account  of  rain.  Seven  of  the  caterpillars  pupated,  four 
of  which  emerged.  Three  of  these  seven  began  pupating 
before  they  had  time  to  eat  any  of  the  poisoned  food. 
Foliage  badly  burned. 

2  Ibs.  Paris  Green  to  150  gal.  Water. 

No.  53.— April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  2  Ibs.  to  150  gal.  of 
water.  Two  died  the  first,  one  the  second,  six  the  third 
and  one  the  fourth  day. 

Check  experiment :  none  dead. 

No.  54.  —  May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green,  in  the  proportion  of  2  Ibs.  to  150  gal.  of  water. 
One  died  the  second,  four  the  third,  one  the  fifth  and  four 
the  sixth  day. 

Check  experiment :  none  dead. 

No.  55.— May  28,  1894.  Ten  caterpillars,  of  the  first 
rnolt,  were  placed  on  lettuce  leaves  which  had  been  treated 


430  THE   GYPSY  MOTH. 

with  Paris  green,  in  the  proportion  of  2  Ibs.  to  150  gal.  of 
water.  Five  died  the  third,  two  the  fourth,  one  the  sixth, 
one  the  seventh  and  one  the  ninth  day. 

Check  experiment :  one  died  the  fourth  day. 

No.  56.  —  June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  2  Ibs.  to  150  gal.  of 
water.  One  died  the  second,  two  the  third,  one  the  fourth, 
four  the  seventh  and  two  the  eighth  day. 

Check  experiment :  none  dead. 

No.  57.  —  June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  2  Ibs.  to  150  gal.  of 
water.  One  died  the  second,  one  the  third,  four  the  fifth, 
two  the  sixth  and  two  the  seventh  day. 

Check  experiment :  one  died  the  seventh  day. 

No.  58.  — June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  2  Ibs.  to  150  gal.  of 
water.  Two  died  the  second,  five  the  third,  one  the  fourth, 
fifth  and  sixth  days. 

Check  experiment :  one  died  the  fourth  and  one  the  sixth 
day. 

No.  59.— July  10,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  2  Ibs.  to  150  gal. 
of  water.  One  pupated  the  fifth  day ;  two  died  and  four 
pupated  the  sixth  day ;  one  pupated  the  seventh  day ;  one 
died  the  tenth  and  one  the  fourteenth  day. 

Check  experiment :  four  pupated  and  one  died  the  fourth 
day ;  one  pupated  the  fifth  day,  one  the  sixth,  one  the  ninth 
and  one  the  eleventh  day. 

No.  60  (field  experiment).  —  July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green,  in  the  proportion 
of  2  Ibs.  to  150  gal.  of  water.  One  pupated  the  fourth  and 
one  died  the  thirteenth  day ;  three  pupated  the  fourteenth 
and  one  died  the  seventeenth  day ;  two  pupated  the  nine- 
teenth and  two  the  twenty-sixth  day.  Foliage  badly  burned. 


INSECTICIDES.  431 


3  Ibs.  Paris  Green  to  150  gal.  Water. 

No.  61.— April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  3  Ibs.  to  150  gal.  of 
water.  Five  died  the  second,  four  the  third  and  one  the 
fifth  day. 

Check  experiment :  none  dead. 

No.  62.  —May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green,  in  the  proportion  of  3  Ibs.  to  150  gal.  of  water. 
Two  died  the  second,  one  the  third,  three  the  fourth,  one 
the  fifth  and  three  the  sixth  day. 

Check  experiment :  none  dead. 

No.  63.  —  May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  3  Ibs.  to  150  gal.  of 
water.  Eight  died  the  third  day,  one  the  seventh  and  one 
the  eighth  day. 

Check  experiment :  none  dead. 

No.  64.  —  June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  3  Ibs.  to  150  gal.  of 
water.  One  died  the  second  day,  one  the  third,  four  the 
fifth,  three  the  seventh  and  one  the  ninth  day. 

Check  experiment :  none  dead. 

No.  65.  —  June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  3  Ibs.  to  150  gal. 
of  water.  One  died  the  second,  two  the  third,  two  the 
fourth,  four  the  fifth  and  one  the  sixth  day. 

Check  experiment :  none  dead. 

No.  66.  —June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on, elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  3  Ibs.  to  150  gal.  of 
water.  Two  died  the  first,  one  the  second,  three  the  third, 
two  the  fourth  and  two  the  sixth  day. 

Check  experiment :  none  dead. 

No.  67.  — July  10,  1894.     Ten  caterpillars,  of  the  fifth 


432  THE   GYPSY  MOTH. 

molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  in  the  proportion  of  3  Ibs.  to  150  gal.  of 
water.  One  died  and  one  pupated  the  third  day ;  one 
pupated  the  fourth  and  one  the  fifth  day ;  one  pupated  and 
one  died  the  sixth  day ;  one  died  the  seventh,  two  the  ninth 
and  one  the  fourteenth  day. 

Check  experiment :  three  pupated  the  fourth  day,  one 
pupated  and  one  died  the  sixth  day ;  one  pupated  and  one 
died  the  ninth  day ;  three  died  the  fourteenth  day. 

No.  68  (field  experiment) .— July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green,  in  the  proportion 
of  3  Ibs.  to  150  gal.  of  water.  One  died  the  third,  one 
the  fourth  and  one  the  fifth  day ;  one  pupated  the  sixth,  one 
the  fifteenth,  one  the  eighteenth,  one  the  twenty-first,  one  the 
twenty-fourth,  one  the  twenty-eighth  and  one  the  thirty- 
first  day.  Foliage  badly  burned. 

4  Ibs.  Paris  Green  to  150  gal  Water. 

No.  69.—  April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  4  Ibs.  to  150  gal.  of 
water.  Five  died  the  second  and  four  the  third  day ;  and 
one  escaped. 

Check  experiment :  none  dead. 

No.  70. — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green,  in  the  proportion  of  4  Ibs.  to  150  gal.  of  water. 
Two  died  the  second,  five  the  third,  one  the  fourth  and  one 
the  fifth  day ;  and  one  escaped. 

Check  experiment :  two  died  the  fourth  day. 

No.  71.— May  28,  1895.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  4  Ibs.  to  150  gal.  of 
water.  One  died  the  fourth,  two  the  fifth  and  seven  the 
sixth  day. 

Check  experiment :  one  died  the  fifth  day. 

No.  72.— June  10,  1894.  Ten  caterpillars,  of  the 
second  molt,  were  placed  on  elm  leaves  which  had  been 


INSECTICIDES.  433 

sprayed  with  Paris  green,  in  the  proportion  of  4  Ibs.  to  150 
gal.  of  water.  Two  died  the  second,  three  the  fourth,  two 
the  fifth,  two  the  sixth  and  one  the  eighth  day. 

Check  experiment :  none  dead. 

No.  73.  —June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  4  Ibs.  to  150  gal.  of 
water.  Four  died  the  second,  four  the  third,  one  the  fifth 
and  one  the  sixth  day. 

Check  experiment :  none  dead. 

No.  74.  —June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  4  Ibs.  to  150  gal.  of 
water.  Four  died  the  third  day ;  two  pupated  the  fourth 
day ;  three  died  the  fifth  and  one  the  sixth  day. 

Check  experiment :  one  died  the  third  day. 

No.  75. — July  10,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  4  Ibs.  to  150  gal.  of 
water.  One  died  the  second  day,  two  pupated  and  two  died 
the  third  day ;  two  pupated  and  one  died  the  sixth  day ;  one 
died  the  seventh  and  one  the  eighth  day. 

Check  experiment :  one  pupated  the  fourth  day ;  one  died 
the  sixth  day. 

No.  76  (field  experiment). — July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green,  in  the  proportion 
of  4  Ibs.  to  150  gal.  of  water.  One  died  and  two  pupated 
the  fifth  day ;  one  died  the  sixth  and  two  the  seventh  day ; 
one  pupated  the  fourteenth,  one  the  fifteenth,  one  the  nine- 
teenth and  one  the  twenty-second  day.  Foliage  badly 
burned. 

5  Ibs.  Paris  Green  to  150  gal.  Water, 

No.  77.  —  April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  5  Ibs.  to  150  gal.  of 
water.  Two  died  the  first  and  seven  the  third  day  ;  and  one 
escaped. 

Check  experiment :  none  dead ;  one  escaped. 


434  THE   GYPSY   MOTH. 

No.  78. — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green,  in  the  proportion  of  5  Ibs.  to  150  gal.  of  water. 
One  died  the  first,  three  the  second,  two  the  third,  three  the 
fourth  and  one  the  fifth  day. 

Check  experiment :  one  died  the  second  day. 

No.  79.— May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  5  Ibs.  to  150  gal.  of 
water.  Five  died  the  third,  three  the  fourth  and  two  the 
sixth  day. 

Check  experiment :  one  died  the  third  day. 

No.  80. — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elni  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  5  Ibs.  to  150  gal.  of 
water.  Two  died  the  second,  three  the  third,  one  the  fourth, 
one  the  fifth,  one  the  sixth,  one  the  seventh  and  one  the 
eighth  day. 

Check  experiment :  none  dead. 

No.  81.  — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  5  Ibs.  to  150  gal.  of 
water.  Six  died  the  second  and  four  the  third  da}^. 

Check  experiment :  none  dead. 

No.  82.  —June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  5  Ibs.  to  150  gal.  of 
water.  Two  died  the  second,  two  the  third  and  two  the 
fourth  day ;  one  died  and  one  pupated  the  fifth  day ;  two 
died  the  eighth  day. 

Check  experiment :  one  died  the  third  day ;  one  pupated 
the  fourth  day ;  two  died  the  fifth  day. 

No.  83. — July  10,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  5  Ibs.  to  150  gal.  of 
water.  Two  died  the  third  day  ;  two  pupated  the  sixth  and 
one  the  seventh  day ;  one  pupated  and  one  died  the  eighth 
day ;  two  died  the  ninth  day ;  one  pupated  the  eleventh 
day. 


INSECTICIDES.  435 

Check  experiment :  five  pupated  the  fourth  and  one  the 
fifth  day ;  one  died  the  eleventh  day. 

No.  84  (field  experiment).-— July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green,  in  the  proportion 
of  5  Ibs.  to  150  gal.  of  water.  One  pupated  the  fourth, 
three  the  seventh,  one  the  thirteenth,  three  the  fourteenth, 
one  the  seventeenth  and  one  the  twenty-first  day.  Foliage 
badly  burned. 

6  Ibs.  Paris  Green  to  150  gal.  Water. 

No.  85.  — April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  6  Ibs.  to  150  gal.  of 
water.  One  died  the  first,  six  the  second  and  three  the  third 
day. 

Check  experiment :  none  dead ;  one  escaped. 

No.  86.  — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green,  in  the  proportion  of  6  Ibs.  to  150  gal.  of  water. 
Five  died  the  second,  one  the  third  and  four  the  fourth  day. 

Check  experiment :  none  dead. 

No.  87. — May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green,  in  the  proportion  of  6  Ibs.  to  150  gal.  of 
water.  Four  died  the  third,  three  the  fourth,  one  the  fifth, 
one  the  seventh  and  one  the  eighth  day. 

Check  experiment :  one  died  the  fourth  day. 

No.  88.  — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  6  Ibs.  to  150  gal.  of 
water.  Four  died  the  first,  one  the  second,  two  the  fourth, 
one  the  fifth  and  one  the  sixth  day ;  one  was  lost. 

Check  experiment :  none  dead. 

No.  89.  —  June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  6  Ibs.  to  150  gal.  of 
water.  Five  died  the  second,  two  the  third,  two  the  fifth 
and  one  the  sixth  day. 

Check  experiment :  none  dead. 


436  THE   GYPSY   MOTH. 

No.  90.  — June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  6  Ibs.  to  150  gal.  of 
water.  Four  died  the  first,  two  the  second,  one  the  third, 
fourth,  fifth  and  sixth  days. 

Check  experiment :  one  died  the  third  day. 

No.  91.— July  10,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green,  in  the  proportion  of  6  Ibs.  to  150  gal.  of 
water.  Two  died  the  third  day ;  one  died  and  one  pupated 
the  fourth  day ;  two  died  and  one  pupated  the  sixth  day ; 
two  died  the  eighth  and  one  the  twelfth  day. 

Check  experiment :  one  pupated  the  fifth  day ;  one  died 
the  seventh  day ;  two  died  and  two  pupated  the  eighth  day ; 
one  pupated  the  ninth  and  one  the  tenth  day. 

No.  92  (field  experiment).— July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green,  in  the  proportion 
of  6  Ibs.  to  150  gal.  of  water.  Two  died  the  fourth,  one 
the  sixth  and  one  the  seventh  da}* ;  one  pupated  the  eighth 
and  one  the  thirteenth  day ;  one  died  the  fourteenth  day ; 
one  pupated  the  fifteenth,  one  the  nineteenth  and  one  the 
twentieth  day.  Foliage  badly  burned. 

Experiments  with  Paris  Green  and  Lime. 
£  lb.  Each  of  Paris  Green  and  Lime  to  150  gal.  Water. 

No.  1. — April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  ^  lb.  each 
to  150  gal.  of  water.  One  died  the  second  and  nine  the 
third  day. 

Check  experiment :  none  dead. 

No.  2.  —  May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green  and  lime,  in  the  proportion  of  £  lb.  each  to  150 
gal.  of  water.  One  died  the  second,  one  the  third,  seven 
the  fifth  and  one  the  sixth  day. 

Check  experiment :  none  dead. 

No.  3.— May  28,  1894.     Ten  caterpillars,   of  the  first 


INSECTICIDES.  437 

molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  £  Ib.  each 
to  150  gal.  of  water.  Three  died  the  third,  two  the  fourth, 
two  the  sixth,  one  the  seventh  and  two  the  eighth  day. 

Check  experiment :  none  dead. 

No.  4.  — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  treated  with 
Paris  green  and  lime,  in  the  proportion  of  £  Ib.  each  to  150 
gal.  of  water.  One  died  the  fourth,  one  the  sixth,  four  the 
ninth,  two  the  tenth  and  two  the  eleventh  day. 

Check  experiment :  none  dead. 

No.  5.  — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lirne^  in  the  proportion  of  £  Ib.  each 
to  150  gal.  of  water.  One  died  the  fourth,  four  the  sixth 
and  five  the  seventh  day. 

Check  experiment :  none  dead. 

No.  6.  —June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  £  Ib.  each 
to  150  gal.  of  water.  Two  died  the  first,  one  the  second, 
fourth,  fifth,  sixth  and  seventh  and  three  the  eighth  day. 

Check  experiment :  one  pupated  the  sixth  day. 

No.  7. — July  11,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  £  Ib.  each 
to  150  gal.  of  water.  One  died  the  first  day;  one  died  and 
one  pupated  the  second  day ;  two  pupated  the  third  day ; 
one  died  the  fifth,  one  the  eighth,  one  the  ninth  and  two  the 
tenth  day. 

Check  experiment :  two  pupated  the  fifth  day ;  one  died 
and  one  pupated  the  eighth  day ;  one  pupated  the  ninth  day. 

No.  8  (field  experiment).  —  July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green  and  lime,  in  the 
proportion  of  £  Ib.  each  to  150  gal.  of  water.  One  died  the 
fourth,  one  the  fifth  and  one  the  seventh  day ;  one  pupated 
the  tenth,  one  the  fourteenth,  one  the  sixteenth  and  four  the 
eighteenth  day. 


438  THE   GYPSY  MOTH. 


|  lb.  Each  Paris  Green  and  Lime  to  150  gal.  Water. 

No.  9.  —  April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  ^  lb.  each 
to  150  gal.  of  water.  Two  died  the  second,  six  the  third 
and  two  the  fourth  day. 

Check  experiment :  none  dead. 

No.  10.— May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green  and  lime,  in  the  proportion  of  |  lb.  each  to  150 
gal.  of  water.  Two  died  the  second,  five  the  third  and  three 
the  fourth  day. 

Check  experiment :  none  dead. 

No.  11. — May  2,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  |  lb.  each 
to  150  gal.  of  water.  One  died  the  third,  one  the  fifth,  four 
the  seventh,  two  the  eighth  and  two  the  ninth  day. 

Check  experiment :  none  dead. 

No.  12.  — June  10,  1895.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  |  lb.  each 
to  150  gal.  of  water.  Two  died  the  sixth,  six  the  seventh 
and  two  the  eighth  day. 

Check  experiment :  none  dead. 

No.  13.— June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  |  lb.  each  to 
150  gal.  of  water.  Four  died  the  fifth,  one  the  sixth,  four 
the  seventh  and  one  the  eighth  day. 

Check  experiment :  none  dead. 

No.  14.  —  June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  |  lb.  each 
to  150  gal.  of  water.  One  died  the  third,  five  the  fourth, 
one  the  fifth,  two  the  sixth  and  one  the  seventh  day. 

Check  experiment :  one  died  the  fourth  day. 

No.  15.  —July  11,  1894.     Ten  caterpillars,  of  the  fifth 


INSECTICIDES.  439 

molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  f  Ib.  each 
to  150  gal.  of  water.  Two  died  the  first  day ;  two  pupated 
the  fifth  day ;  three  died  the  ninth,  two  the  tenth  and  one 
the  fourteenth  day. 

Check  experiment:  one  lost  and  one  pupated  the  third 
day;  one  pupated  the  fourth,  one  the  fifth  and  one  the 
.sixth  day ;  one  died  the  eighth,  three  the  twelfth  and  one 
the  thirteenth  day. 

No.  16  (field  experiment). — July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green  and  lime,  in  the 
proportion  of  f  Ib.  each  to  150  gal.  of  water.  Two  died  the 
third  day;  two  pupated  the  sixth  and  one  the  thirteenth 
day;  one  died  and  one  pupated  the  fourteenth  day;  one 
died  and  two  pupated  the  eighteenth  day. 

1  Ib.  Each  Paris  Green  and  Lime  to  150  gal.  Water. 

No.  17. — April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  1  Ib.  each 
to  150  gal.  of  water.  Eight  died  the  second,  one  the  fourth 
and  one  the  fifth  day. 

Check  experiment :  none  dead ;  five  escaped. 

No.  18.— May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green  and  lime,  in  the  proportion  of  1  Ib.  each  to  150 
gal.  of  water.  One  died  the  second,  six  the  third,  one  the 
fourth,  one  the  fifth  and  one  the  sixth  day. 

Check  experiment :  one  died  the  second  day. 

No.  19.  —  May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  1  Ib.  each  to 
150  gal.  of  water.  One  died  the  fourth,  two  the  fifth,  three 
the  sixth,  two  the  eighth,  one  the  ninth  and  one  the  tenth  day. 

Check  experiment :  one  died  the  sixth  day. 

No.  20.  —  June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  1  Ib.  each 


440  THE   GYPSY   MOTH. 

to  150  gal.  water.     One  died  the  second,  four  the  sixth,  four 
the  seventh  and  one  the  tenth  day. 
Check  experiment :  none  dead. 

No.  21.  — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  1  Ib.  each 
to  150  gal.  of  water.  One  died  the  third,  two  the  fifth,  two 
the  sixth  and  five  the  seventh  day. 

Check  experiment :   one  died  and  one  lost  the  seventh  day. 
No.  22.  — June  29,  1894.     Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  1  Ib.  each 
to  150  gal.  of  water.     Three  died  the  second,  two  the  third 
and  one  the  fourth,  fifth,  sixth,  seventh  and  eighth  days. 
Check  experiment :  one  died  the  third  day. 
No.  23. — July  11,  1894.     Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  1  Ib.  each  to 
150  gal.  of  water.     One  died  and  one  pupated  the  second 
day;    two  pupated  the  fourth,   two  the  fifth  and  one  the 
eighth  day ;    two  died  the  tenth  and  one  the  fourteenth  day. 
Check  experiment :  one  died  and  one  pupated  the  third 
day ;  one  died  the  seventh,  one  the  eighth  and  one  the  tenth 
day. 

No.  24  (field  experiment). — Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  willow  branches  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  1  Ib:  each  to 
150  gal.  of  water.  One  died  the  sixth  and  three  the  seventh 
day ;  one  pupated  the  eleventh,  one  the  twelfth,  two  the  thir- 
teenth, one  the  fifteenth  and  one  the  seventeenth  day. 

Ik  Ibs.  Each  Paris  Green  and  Lime  to  150  gal.  Water. 

No.  25.  — April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  1J  Ibs.  each 
to  150  gal.  of  water.  Five  died  the  second,  two  the  third 
and  one  the  fourth  day,  and  two  escaped. 

Check  experiment:  one  died  the  fifth  day,  and  five  es- 
caped. 


INSECTICIDES.  441 

No.  26.— May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green  and  lime,  in  the  proportion  of  1£  Ibs.  each  to 
150  gal.  of  water.  Four  died  the  second,  five  the  third  and 
one  the  fourth  day. 

Check  experiment :  one  died  the  second  day. 

No.  27. —  May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  1£  Ibs.  each 
to  150  gal.  of  water.  Four  died  the  third,  one  the  fourth, 
two  the  fifth  and  three  the  sixth  day. 

Check  experiment :  one  died  the  fifth  day. 

No.  28.  — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  1£  Ibs.  each 
to  150  gal.  of  water.  One  died  the  second,  one  the  fourth, 
four  the  sixth,  three  the  seventh  and  one  the  eighth  day. 

Check  experiment :  none  dead. 

No.  29. — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  1J  Ibs.  each 
to  150  gal.  of  water.  Three  died  the  third,  one  the  fourth, 
four  the  fifth  and  two  the  sixth  day. 

Check  experiment :  none  dead. 

No.  30.  —June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  1J  Ibs.  each 
to  150  gal.  of  water.  Four  died  the  third,  two  the  fourth, 
two  the  fifth  and  two  the  sixth  day. 

Check  experiment :  one  pupated  the  fourth  day. 

No.  31. — July  11,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  1J  Ibs.  each 
to  150  gal.  of  water.  Two  pupated  the  third  and  one  the 
fifth  day ;  two  died  and  one  pupated  the  seventh  day ;  one 
died  the  eighth,  two  the  ninth  and  one  the  eleventh  day. 

Check  experiment :  one  died  the  third  day ;  one  pupated 
the  fourth,  two  the  fifth,  one  the  eighth  and  one  the  tenth 
day. 


442  THE   GYPSY   MOTH. 

No.  32  (field  experiment). —July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green  and  lime,  in  the 
proportion  of  1£  Ibs.  each  to  150  gal.  of  water.  One  died 
the  fourth  day ;  one  died  and  one  pupated  the  seventh  day ; 
one  pupated  the  ninth,  one  the  thirteenth,  one  the  sixteenth, 
two  the  eighteenth,  one  the  twenty-sixth  and  one  the  twenty- 
eighth  day. 

2  Ibs.  Each  Paris  Green  and  Lime  to  150  gal.  Water. 

No.  33.  —  April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  2  Ibs.  each 
to  150  gal.  of  water.  Three  died  the  second,  four  the  third 
and  three  the  fourth  day. 

Check  experiment :  none  dead. 

No.  34. — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green  and  lime,  in  the  proportion  of  2  Ibs.  each  to 
150  gal.  of  water.  One  died  the  second,  five  the  third,  two 
the  fourth  and  two  the  fifth  day. 

Check  experiment :  none  dead. 

No.  35.— May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  2  Ibs.  each 
to  150  gal.  of  water.  One  died  the  third,  one  the  fourth, 
one  the  fifth,  two  the  sixth,  four  the  seventh  and  one  the 
eighth  day. 

Check  experiment :  none  dead. 

No.  36. — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  2  Ibs.  each 
to  150  gal.  of  water.  One  died  the  second,  one  the  fourth, 
two  the  fifth,  three  the  sixth  and  three  the  seventh  day. 

Check  experiment :  none  dead. 

No.  37.— June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  2  Ibs.  each 
to  150  gal.  of  wTater.  TNVO  died  the  second,  two  the  third, 
one  the  fifth,  three  the  sixth  and  two  the  seventh  day. 


..    INSECTICIDES.  443 

Check  experiment :  two  lost  the  seventh  day. 

No.  38.  —June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  2  Ibs.  each 
to  150  gal.  of  water.  Two  died  the  second,  two  the  third, 
two  the  fourth,  two  the  fifth,  one  the  sixth  and  one  the 
eighth  day. 

Check  experiment :  one  died  the  fourth,  one  the  fifth  and 
one  the  sixth  day. 

No.  39.— July  11,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  2  Ibs.  each  to 
150  gal.  of  water.  Two  pupated  the  second  day ;  one  died 
the  third  day ;  one  died  and  one  pupated  the  fifth  day  ;  one 
pupated  the  sixth  day ;  one  died  the  seventh,  one  the  ninth 
and  two  the  tenth  day. 

Check  experiment :  one  died  the  third  day ;  two  died  and 
two  pupated  the  ninth  day. 

No.  40  (field  experiment). — July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green  and  lime,  in  the 
proportion  of  2  Ibs.  each  to  150  gal.  of  water.  One  pupated 
the  sixth  day ;  two  died  the  seventh  day ;  one  pupated  the 
eighth  day ;  one  died  and  one  pupated  the  thirteenth  day ; 
one  pupated  the  fourteenth,  one  the  sixteenth,  one  the 
twentieth  and  one  the  twenty-second  day. 

3  Ibs.  Each  Paris  Green  ay,d  Lime  to  150  gal.  Water. 

No.  41.  —  April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  3  Ibs.  each 
to  150  gal.  of  water.  Four  died  the  second,  two  the  third, 
one  the  fourth  and  three  the  fifth  day. 

Check  experiment :  none  dead. 

No.  42.  — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green  and  lime,  in  the  proportion  of  3  Ibs.  each  to  150 
gal.  of  water.  Two  died  the  second,  three  the  third,  one 
the  fourth  and  four  the  fifth  day. 


444  THE   GYPSY   MOTH. 

Check  experiment :  none  dead. 

No.  43.  —  May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  3  .Ibs.  each 
to  150  gal.  of  water.  One  died  the  third,  three  the  fifth, 
four  the  sixth  and  two  the  seventh  day. 

Check  experiment :  none  dead. 

No.  44.— June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  3  Ibs.  each 
to  150  gal.  of  water.  One  died  the  second,  two  the  third, 
one  the  fourth,  two  the  fifth,  three  the  sixth  and  one  the 
seventh  day. 

Check  experiment :  none  dead. 

No.  45.— June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  3  Ibs.  each 
to  150  gal.  of  water.  Five  died  the  third,  two  the  sixth  and 
three  the  seventh  day. 

Check  experiment :  two  died  the  seventh  day. 

No.  46. — June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  eim  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  3  Ibs.  each 
to  150  gal.  of  water.  Two  died  the  first,  one  the  second, 
two  the  third,  one  the  fourth,  one  the  fifth,  two  the  sixth 
and  one  the  seventh  day. 

Check  experiment :  none  dead. 

No.  47.— July  11,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  3  Ibs.  each 
to  150  gal.  of  water.  Two  pupated  the  second  and  one  the 
third  day ;  two  died  the  seventh  and  four  the  ninth  day ; 
one  pupated  the  eleventh  day. 

Check  experiment :  one  died  the  third  day ;  two  pupated 
the  fifth  day ;  one  died  the  eighth  and  one  the  tenth  day. 

No.  48  (field  experiment). —July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green  and  lime,  in  the 
proportion  of  3  Ibs.  each  to  150  gal.  of  water.  One  died 
the  fourth  and  two  the  fifth  day ;  two  died  and  one  pupated 


INSECTICIDES.  445 

the  seventh  day ;  one  pupated  the  tenth,  one  the  fourteenth, 
one  the  fifteenth  and  one  the  twenty-first  day. 

4  Ibs.  Each  Paris  Green  and  Lime  to  150  gal.  Water. 

No.  49.  —  April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  4  Ibs.  each 
to  150  gal.  of  water.  Six  died  the  second  and  four  the  third 
day. 

Check  experiment :  none  dead. 

No.  50.  —May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green  and  lime,  in  the  proportion  of  4  Ibs.  each  to  150 
gal.  of  water.  Five  died  the  second,  four  the  third  and  one 
the  fifth  day. 

Check  experiment :  none  dead. 

No.  51. — May  28,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  4  Ibs.  each 
to  150  gal.  of  water.  Three  died  the  fourth,  three  the  fifth, 
three  the  sixth  and  one  the  seventh  day. 

Check  experiment :  none  dead. 

No.  52.  — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  4  Ibs.  each 
to  150  gal.  of  water.  One  died  the  third,  two  the  fourth, 
three  the  fifth  and  four  the  seventh  day. 

Check  experiment :  none  dead. 

No.  53. — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  4  Ibs.  each 
to  150  gal.  of  water.  Three  died  the  second,  four  the  third, 
one  the  fifth  and  two  the  sixth  day. 

Check  experiment :  none  dead. 

No.  54.  — June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  were  sprayed  with 
Paris  green  and  lime,  in  the  proportion  of  4  Ibs.  each  to  150 
gal.  of  water.  One  died  the  first,  one  the  second,  two  the 
third,  four  the  fourth  and  two  the  fifth  day. 

Check  experiment :  none  dead. 


446  THE   GYPSY   MOTH. 

No.  55.  —  July  11,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  4  Ibs.  each 
to  150  gal.  of  water.  Three  pupated  the  second  day ;  one 
died  the  third,  one  the  fourth,  one  the  fifth,  two  the  sixth, 
one  the  seventh  and  one  the  eighth  day. 

Check  experiment :  two  pupated  the  third,  one  the  fourth 
and  one  the  sixth  day. 

No.  56  (field  experiment) .— July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green  and  lime,  in  the 
proportion  of  4  Ibs.  each  to  150  gal.  of  water.  One  died 
the  fourth,  one  the  fifth,  one  the  sixth  and  one  the  seventh 
day  ;  one  pupated  the  ninth  day  ;  one  died  and  one  pupated 
the  tenth  day ;  one  pupated  the  thirteenth,  one  the  seven- 
teenth and  one  the  eighteenth  day. 


5  Ibs.  Each  Paris  Green  and  Lime  to  150  gal.  Water. 

No.  57.  —  April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  5  Ibs.  each 
to  150  gal.  of  water.  One  died  the  first,  two  the  second  and 
five  the  third  day  ;  and  two  escaped. 

Check  experiment :  none  dead. 

No.  58. — May  9,  1895.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green  and  lime,  in  the  proportion  of  5  Ibs.  each  to  150 
gal.  of  water.  One  died  the  second,  one  the  third,  five  the 
fourth  and  three  the  fifth  day. 

Check  experiment :  none  dead. 

No.  59.— May  28,  1894.     Ten  caterpillars,  of  the  first 

molt,  were  placed  on  lettuce  leaves  which  had  been  treated 

with  Paris  green  and  lime,  in  the  proportion  of  5  Ibs.  each 

kto  150  gal.  of  water.     Two  died  the  third,  one  the  fourth, 

two  the  fifth,  three  the  sixth  and  two  the  eighth  day. 

Check  experiment :  none  dead. 

No.  60.  —  June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  5  Ibs.  each 


INSECTICIDES.  447 

to  150  gal.  of  water.  Four  died  the  second,  one  the  third, 
two  the  fourth,  two  the  fifth  and  one  the  sixth  day. 

Check  experiment :  none  dead. 

No.  61.— June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  5  Ibs.  each 
to  150  gal.  of  water.  Two  died  the  second,  one  the  third, 
two  the  fourth,  two  the  sixth,  two  the  seventh  and  one  the 
eighth  day. 

Check  experiment :  one  died  the  seventh  day. 

No.  62.  — June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  5  Ibs.  each 
to  150  gal.  of  water.  Two  died  the  second,  four  the  third, 
three  the  fourth  and  one  the  sixth  day. 

Check  experiment :  none  dead. 

No.  63.— July  11,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  5  Ibs.  each 
to  150  gal.  of  water.  Two  pupated  and  two  died  the  second 
day ;  one  died  and  one  pupated  the  third  day  ;  one  died  the 
seventh  and  three  the  eighth  day. 

Check  experiment :  two  pupated  the  third  day  ;  one  died 
and  three  pupated  the  fifth  day;  one  pupated  the  eighth 
day. 

No.  64  (field  experiment) .— July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green  and  lime,  in  the 
proportion  of  5  Ibs.  each  to  150  gal.  of  water.  One  died  the 
fourth,  one  the  fifth,  one  the  sixth  and  one  the  seventh  day  ; 
two  died  and  one  pupated  the  eighth  day  ;  one  pupated  and 
one  was  lost  the  fourteenth  day;  one  pupated  the  thirty- 
third  day. 

6  Ibs.  Each  Paris  Green  and  Lime  to  150  gal.  Water. 
No.  65. — April  26,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  6  Ibs.  each 
to  150  gal.  of  water.  Six  died  the  second,  three  the  third 
and  one  the  fourth  day. 


448  THE   GYPSY  MOTH. 

Check  experiment :  none  dead. 

No.  66.  — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
Paris  green  and  lime,  in  the  proportion  of  6  Ibs.  each  to  150 
gal.  of  water.  One  died  the  second,  three  the  third,  three 
the  fourth  and  three  the  fifth  day. 

Check  experiment :  one  died  the  third  day. 

No.  67.— May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  Paris  green  and  lime,  in  the  proportion  of  6  Ibs.  each 
to  150  gal.  of  water.  Six  died  the  third,  two  the  fourth, 
one  the  fifth  and  one  the  sixth  day. 

Check  experiment :  none  dead. 

No.  68. — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  treated  with 
Paris  green  and  lime,  in  the  proportion  of  6  Ibs.  each  to  150 
gal.  of  water.  Three  died  the  second,  three  the  third,  two 
the  fifth,  one  the  sixth  and  one  the  seventh  day. 

Check  experiment :  none  dead. 

No.  69.  —June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed  with 
Paris  green  and  lime,  in  the  proportion  of  6  Ibs.  each  to  150 
gal.  of  water.  Two  died  the  second,  one  the  third,  two  the 
fourth,  one  the  sixth  and  four  the  seventh  day. 

Check  experiment :  one  accidentally  killed  the  seventh  day. 

No.  70.  — June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  6  Ibs.  each  to 
150  gal.  of  water.  Six  died  the  second,  two  the  third  and 
two  the  fourth  day. 

Check  experiment  •  one  died  the  third  day. 

No.  71.— July  11,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  Paris  green  and  lime,  in  the  proportion  of  6  Ibs.  each  to 
150  gal.  of  water.  One  died  the  first  day;  one  died  and 
two  pupated  the  second  day ;  one  died  the  third  day ;  one 
pupated  the  filth  day ;  three  died  the  seventh  and  one  the 
eleventh  day. 

Check  experiment :  one  pupated  the  third  day ;  one  died 
and  four  pupated  the  fifth  day ;  one  died  the  tenth  day. 


INSECTICIDES.  449 

No.  72  (field  experiment). — July  7,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  Paris  green  and  lime,  in  the 
proportion  of  6  Ibs.  each  to  150  gal.  of  water.  One  died 
the  fourth,  one  the  sixth,  two  the  seventh  and  one  the  eighth 
day ;  one  pupated  the  fourteenth,  one  the  fifteenth,  one  the 
sixteenth  and  two  the  eighteenth  day. 

Experiments  with  Arsenate  of  Lead. 
\  lb.  Arsenate  of  Lead  to  150  gal.  Water. 

No.  1.  —  March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  |  lb.  to  150  gal. 
of  water.  One  died  the  fifth,  one  the  sixth  and  one  the 
seventh  day ;  those  remaining  lived  and  molted. 

No.  2. —  May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves,  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  ^  lb.  to  150  gal.  of 
water.  One  died  the  fifth  day ;  those  remaining  lived  and 
molted. 

Check  experiment :  none  dead. 

No.  3.  — May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  £  lb.  to  150  gal. 
of  water.  All  lived  through  the  experiment. 

Check  experiment :  none  dead. 

No.  4. — June  10,  1894.  Te.n  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  ^  lb.  to  150  gal. 
of  water.  All  lived  through  the  experiment. 

Check  experiment :  none  dead. 

No.  5.— June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  |  lb.  to  150  gal. 
of  water.  One  died  the  seventh,  three  the  eighth  and  one 
the  ninth  day;  one  pupated  the  tenth  day;  one  died  the 
eleventh  day.  The  remainder  lived  through  the  experiment. 

Check  experiment :  one  was  lost  the  seventh  day ;  one 
pupated  the  eighth  day ;  two  died  the  tenth  day. 


450  THE    GYPSY   MOTH. 


£  lb.  Ar senate  of  Lead  to  150  gal  Water. 

No.  6. — March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  upon  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  ^  lb  to  150  gal. 
of  water.  On  the  ninth  day  six  were  dead  and  four  lost. 

No.  7. — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  \  lb.  to  150  gal.  of 
water.  All  lived  through  the  experiment  (seventeen  days). 

Check  experiment :  none  dead. 

No.  8.  —May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  J  lb.  to  150  gal. 
of  water.  One  died  the  third,  one  the  fourth,  one  the 
seventh  and  one  the  ninth  day ;  the  remainder  lived  through 
the  experiment. 

Check  experiment :  none  dead. 

No.  9. — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  £  lb.  to  150  gal. 
of  water.  One  died  the  fifth  and  two  the  eleventh  day ;  the 
remainder  lived  through  the  experiment. 

Check  experiment :  none  dead. 

No.  10.— June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  \  lb.  to  150  gal. 
of  water.  One  died  the  fourth,  one  the  fifth  and  one  the 
sixth,  two  died  and  one  pupated  the  seventh,  two  died  the 
eighth,  one  the  tenth  and  one  the  eleventh  day. 

Check  experiment :  one  died  the  seventh  and  one  the 
ninth  day ;  one  was  lost  the  tenth  day. 

No.  11  (field  experiment). — June  29,  1893.  A  branch 
of  oak  was  sprayed  with  arsenate  of  lead,  in  the  proportion 
of  \  lb.  to  150  gal.  of  water,  and  nine  fourth-molt  caterpil- 
lars placed  upon  it.  July  31,  for  lack  of  food,  they  were 
transferred  to  a  fresh  branch,  which  was  left  unsprayed.  All 
these  caterpillars  pupated  and  six  emerged.  Foliage  unin- 
jured. 

No.  12  (field  experiment). — June  29,  1893.     A  branch 


INSECTICIDES.  451 

of  oak  was  sprayed  with  arsenate  of  lead,  in  the  proportion 
of  ^  Ib.  to  150  gal.  of  water,  and  ten  caterpillars,  of  the 
fourth  molt,  were  placed  upon  it.  Three  of  these  died  before 
pupating,  the  last  one  dying  thirty-seven  days  after  the  first 
spraying.  Of  the  seven  that  pupated,  all  emerged.  Foliage 
uninjured. 

No.  13  (field  experiment).— June  29,  1893.  A  branch 
of  a  small  oak  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  \  Ib.  to  150  gal.  of  water,  and  ten  fifth-molt 
caterpillars  placed  upon  it.  July  20,  the  branch  was  re- 
sprayed  on  account  of  the  rain  on  the  18th.  Only  one  cater- 
pillar died  before  pupating,  and  seven  were  able  to  complete 
the  process  of  pupation  and  emerge.  Another  one  fed  on 
the  leaves  for  nine  days  after  the  spraying  and  pupated,  but 
was  injured  in  removing,  and  therefore  not  counted  in  the 
above  summary.  Foliage  uninjured. 

No.  14  (field  experiment).  — June  29,  1893.  A  branch 
of  a  small  oak  tree  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  \  Ib.  to  150  gal.  of  water,  and  nine  fifth-molt 
caterpillars  were  placed  upon  it.  July  20,  the  branch  was 
resprayed  on  account  of  rain.  Only  one  caterpillar  died 
before  pupating,  and  that  on  the  forty-first  day  after  the  first 
spraying.  Of  the  eight  that  pupated,  two  died  without 
emerging.  Foliage  uninjured. 

\  Ib.  Arsenate  of  Lead  to  150  gal  Water. 

No.  15.  —  March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  \  Ib.  to  150  gal. 
of  water.  On  the  eighth  day  all  were  dead. 

No.  16. — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  £  Ib.  to  150  gal.  of 
water.  One  died  the  fifth  day ;  the  remainder  lived  through 
the  experiment  and  molted. 

Check  experiment :  none  dead. 

No.  17. — May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  £  Ib.  to  150  gal. 
of  water.  One  died  the  third,  one  the  fourth,  two  the  fifth, 


452  THE   GYPSY  MOTH. 

one  the  tenth  and  one  the  eleventh  day ;  the  remainder  lived 
through  the  experiment. 

Check  experiment :  none  dead. 

No.  18.  — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  £  Ib.  to  150  gal. 
of  water.  Two  died  the  fifth,  one  the  seventh,  three  the 
eighth,  two  the  ninth,  one  the  tenth  and  one  the  twelfth  day. 

Check  experiment :  none  dead. 

No.  19.  —  June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed  with 
arsenate  of  lead,  in  the  proportion  of  £  Ib.  to  150  gal.  of 
water.  Two  died  the  third,  three  the  seventh,  two  the 
eighth,  one  the  tenth  and  two  the  twelfth  day. 

Check  experiment :  two  died  the  seventh  and  one  the 
eighth  day ;  two  were  lost. 

No.  20  (field  experiment).  —  June  28,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  £  Ib.  to  150  gal.  of  water,  and  ten  fourth-molt 
caterpillars  placed  upon  it.  On  the  19th  of  July,  the  food 
having  given  out  and  two  of  the  caterpillars  having  died, 
those  remaining  were  transferred  to  a  freshly  sprayed  branch. 
Of  the  ten,  two  died  before  pupating,  and  of  the  eight  that 
pupated,  five  emerged.  Foliage  uninjured. 

No.  21  (field  experiment). — June  28,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  £  Ib.  to  150  gal.  of  water,  and  nine  fourth- 
molt  caterpillars  placed  upon  it.  July  19,  as  the  food  supply 
was  nearly  gone,  the  caterpillars  were  removed  to  a  freshly 
sprayed  branch.  One  died  before  beginning  to  pupate,  and 
of  the  eight  which  pupated,  six  emerged.  Foliage  unin- 
jured. 

No.  22  (field  experiment). — June  29,  1893.  A  branch 
of  a  small  oak  tree  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  %  Ib.  to  150  gal.  of  water,  and  nine  fourth- 
molt  caterpillars  were  placed  upon  it.  July  20,  they  were 
transferred  to  a  freshly  sprayed  branch,  both  on  account  of 
the  food  supply  and  rain.  It  was  noticeable  that  on  the  old 
branch  the  caterpillars  had  eaten  all  of  the  old,  tough  leaves, 
and  left  the  young  and  fresh  ones.  Two  died  before  pupat- 


INSECTICIDES.  453 

ing,  and,  of  the  seven  that  pupated,  four  emerged.     Foliage 
uninjured. 

No.  23  (field  experiment). — June  29,  1893.  An  oak 
branch  was  sprayed  with  arsenate  of  lead,  in  the  proportion 
of  3.  Ib.  to  150  gal.  of  water,  and  ten  fourth-molt  caterpillars 
were  placed  upon  it.  July  20,  the  branch  was  resprayed  on 
account  of  rain.  One  died  before  pupating,  and  eight  of 
the  nine  that  pupated  emerged.  Foliage  uninjured. 

No.  24  (field  experiment).  —  June  28,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  £  Ib.  to  150  gal.  of  water,  and  nine  fifth-molt 
caterpillars  placed  upon  it.  On  the  19th  of  July,  they  were 
removed  to  a  freshly  sprayed  branch.  Of  the  eight  that 
pupated,  six  emerged.  Foliage  uninjured. 

No.  25  (field  experiment) .  — June  28,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  £  Ib.  to  150  gal.  of  water,  and  ten  fifth-molt 
caterpillars  placed  upon  it.  July  15,  as  the  food  supply  was 
getting  low,  the  caterpillars  were  removed  to  another  branch 
which  was  not  sprayed.  Three  died  before  pupating,  and,  of 
the  seven  which  pupated,  six  emerged.  Foliage  uninjured. 

No.  26.  —  June  29,  1893.  An  oak  branch  was  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  £  Ib.  to  150  gal. 
of  water,  and  nine  fifth-molt  caterpillars  placed  upon  it. 
July  5,  they  were  transferred  to  a  freshly  sprayed  branch. 
Only  one  of  these  caterpillars  died  before  beginning  to 
pupate,  and,  of  those  that  pupated,  seven  emerged.  Foliage 
uninjured. 

No.  27  (field  experiment). — June  29,  1893.  A  branch 
of  oak  was  sprayed  with  arsenate  of  lead,  in  the  proportion 
of  £  Ib.  to  150  gal.  of  water,  and  ten  fifth-molt  caterpillars 
placed  upon  it.  July  15,  for  lack  of  food,  they  were  trans* 
ferred  to  a  freshly  sprayed  branch.  None  of  these  cater- 
pillars died  before  pupating,  and  five  emerged.  Foliage 
uninjured. 

|  Ib.  Arsenate  of  Lead  to  150  gal  Water. 

No.  28.— March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  f  Ib.  to  150  gal. 
of  water.  On  the  fourth  day  one  died,  on  the  fifth  three,  on 


454  THE   GYPSY  MOTH. 

the  sixth  two  and  on  the  seventh  three ;  the  remaining  one 
was  lost. 

No.  29. — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  f  Ib.  to  150  gal.  of 
water.  All  lived  through  the  experiment. 

Check  experiment :  none  dead. 

No.  30. — May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  |  Ib.  to  150  gal. 
of  water.  One  died  the  eighth  and  three  the  tenth  day ; 
those  remaining  lived  through  the  experiment. 

Check  experiment :  none  dead. 

No.  31.  — June  10, 1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  |  Ib.  to  150  gal. 
of  water.  Two  died  the  fifth,  one  the  ninth,  one  the 
eleventh,  two  the  thirteenth  and  four  the  eighteenth  day. 

Check  experiment :  none  dead. 

No.  32.— June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  f  Ib.  to  150  gal. 
of  water.  One  died  the  third,  one  the  seventh  and  one  the 
ninth  day ;  one  pupated  the  tenth  day ;  one  died  and  one 
pupated  the  eleventh  day ;  and  four  died  the  twelfth  day. 

Check  experiment :  one  pupated  the  tenth  day  and  "two 
died  the  eleventh  day. 

No.  33  (field  experiment). — June  27,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  f  Ib.  to  150  gal.  of  water,  and  nine  fourth- 
molt  caterpillars  placed  upon  it.  Of  these,  three  died  before 
pupating,  and,  of  the  six  which  pupated,  three  emerged. 
Foliage  uninjured. 

No.  34  (field  experiment). — June  27,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  |  Ib.  to  150  gal.  of  water,  and  nine  fourth- 
molt  caterpillars  placed  upon  it.  Of  these,  seven  pupated 
and  emerged,  one  began  pupating  but  died  later,  and  one 
died  in  the  larval  stage.  Foliage  uninjured. 

No.  35   (field  experiment). — June  27,  1893.     A  branch 


INSECTICIDES.  455 

of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  off  Ib.  to  150  gal.  of  water,  and  ten  caterpillars, 
of  the  fourth  molt,  placed  upon  it.  July  8,  the  foliage  was 
so  badly  burned  that  the  nine  remaining  caterpillars  were 
transferred  to  a  freshly  sprayed  branch  of  oak.  By  the  19th 
of  July  all  were  dead.  The  foliage  of  the  oak  was  slightly 
burned. 

No.  36  (field  experiment) .  — June  27,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  |  Ib.  to  150  gal.  of  water,  and  ten  fifth-molt 
caterpillars  placed  upon  it.  All  died  without  pupating. 

No.  37  (field  experiment). —June  27,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  |  Ib.  to  150  gal.  of  water,  and  nine  fifth-molt 
caterpillars  placed  upon  it.  Of  these,  only  one  completed 
the  process  of  pupation  and  emerged,  three  having  died 
before  beginning  to  pupate.  Foliage  uninjured. 

1  Ib.  Arsenate  of  Lead  to  150  gal.  Water. 

No.  38.— March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  1  Ib.  to  150  gal. 
of  water.  One  died  the  fifth,  three  the  sixth  and  one  the 
seventh  day ;  and  five  were  lost. 

No.  39.  —  May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  1  Ib.  to  150  gal.  of 
water.  All  lived  through  the  experiment  and  molted. 

Check  experiment :  none  dead. 

No.  40.— May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  1  Ib.  to  150  gal. 
of  water.  Four  died  the  fourth,  one  the  seventh,  one  the 
eighth  and  one  the  ninth  day ;  the  remainder  lived  through 
the  experiment. 

Check  experiment :  one  died  the  third  and  one  the  seventh 
day. 

No.  41. — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  1  Ib.  to  150  gal. 


456  THE   GYPSY   MOTH. 

of  water.     One  died  the  second,  one  the  seventh,  three  the 
ninth,  four  the  tenth  and  one  the  eleventh  day. 

Check  experiment :  none  dead. 

No.  42. — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  1  Ib.  to  150  gal. 
of  water.  One  died  the  fifth,  two  the  sixth,  three  the  seventh 
and  four  the  eighth  day. 

Check  experiment :  one  died  the  seventh  and  one  the 
eighth  day. 

No.  43.  —  June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  1  Ib.  to  150  gal. 
of  water.  One  died  the  second,  one  the  third,  two  the 
fourth  and  one  the  fifth,  sixth,  seventh,  eighth,  ninth  and 
tenth  days. 

Check  experiment :  one  lost  and  one  dead  the  seventh  day. 

No.  44  (field  experiment).  —June  26,  1893.  An  apple- 
tree  branch  was  sprayed  with  arsenate  of  lead,  in  the  pro- 
portion of  1  Ib.  to  150  gal.  of  water,  and  eight  fourth-molt 
caterpillars  placed  upon  it.  Of  these,  only  one  died  before 
pupating,  and,  of  the  seven  which  pupated,  three  emerged. 
Foliage  uninjured. 

No.  45  (field  experiment) .  — June  26,  1893.  A  branch 
of  an  apple  tree  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  1  Ib.  to  150  gal.  of  water,  and  eight  fourth- 
molt  caterpillars  placed  upon  it.  Of  these,  six  died  before 
pupating,  and,  of  the  two  which  pupated,  one  emerged. 
Foliage  uninjured. 

No.  46.  —July  9,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  1  Ib.  to  150  gal. 
of  water.  One  died  and  one  pupated  the  second  day  ;  one 
died  the  third,  one  the  fourth,  two  the  fifth,  one  the  seventh, 
tenth,  eleventh  and  sixteenth  days. 

Check  experiment :  one  pupated  the  third  day ;  one  died 
the  seventh,  eighth,  ninth  and  eleventh  days ;  two  pupated 
the  twelfth  day ;  one  died  the  thirteenth  and  one  the  four- 
teenth day ;  and  one  was  living  at  the  close  of  the  experi- 
ment. 


INSECTICIDES.  457 

No.  47  (field  experiment) .  — July  9,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  arsenate  of  lead,  in  the  pro- 
portion of  1  Ib.  to  150  gal.  of  water.  One  pupated  the  fifth 
and  one  the  sixth  day ;  one  died  and  one  pupated  the  seventh 
day  ;  one  pupated  the  twelfth  day ;  one  died  the  thirteenth, 
one  the  fifteenth  and  one  the  sixteenth  day ;  one  pupated  the 
twenty-fourth  and  one  the  twenty-eighth  day. 

No.  48  (field  experiment).  —June  26,  1893.  An  apple- 
tree  branch  was  sprayed  with  arsenate  of  lead,  in  the  pro- 
portion of  1  Ib.  to  150  gal.  of  water,  and  eight  fifth-molt 
caterpillars  placed  upon  it.  Of  these,  only  one  died  before 
pupating,  and,  of  those  that  pupated,  one  died  without 
emerging.  Foliage  uninjured. 

No.  49  (field  experiment).  —  June  26,  1893.  An  apple- 
tree  branch  was  sprayed  with  arsenate  of  lead,  in  the  pro- 
portion of  1  Ib.  to  150  gal.  of  water,  and  ten  fifth-molt 
caterpillars  placed  upon  it.  One  of  these  died  before  pupat- 
ing, and,  of  the  remaining  nine,  eight  completed  the  process 
of  pupation  and  emerged.  The  foliage  was  uninjured. 

No.  50  (field  experiment). — July  1,  1893.  A  small  oak 
branch  was  sprayed  with  arsenate  of  lead,  in  the  proportion 
of  1  Ib.  to  150  gal.  of  water,  and  ten  large  fifth-molt  cater- 
pillars placed  upon  it.  All  died  within  twelve  days  after 
spraying.  Foliage  uninjured. 

1^  Ib.  Arsenate  of  Lead  to  150  gal.  Water. 

No.  51.— March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  li  Ibs.  to  150 
gal.  of  water.  One  died  the  fourth,  three  the  fifth,  one  the 
sixth  and  one  the  twelfth  day;  those  remaining  lived 
through  the  experiment. 

No.  52. — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  1£  Ibs.  to  150  gal.  of 
water.  Three  died  the  fifth  day ;  the  remainder  lived  through 
the  experiment  and  molted. 

Check  experiment :  none  dead. 

No.  53. — May  28,  1894.     Ten  caterpillars,  of  the   first 


458  THE   GYPSY   MOTH. 

molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  1J  Ibs.  to  150 
gal.  of  water.  One  died  the  third,  one  the  fourth,  two  the 
fifth,  three  the  sixth  and  two  the  ninth  day ;  the  remainder 
lived  through  the  experiment. 

Check  experiment :  none  dead. 

No.  54.  —June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  1£  Ibs.  to  150 
gal.  of  water.  One  died  the  fifth,  two  the  sixth,  one  the 
seventh,  two  the  eighth,  three  the  ninth  and  one  the  eleventh 
day. 

Check  experiment :  none  dead. 

No.  55.— June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed  with 
arsenate  of  lead,  in  the  proportion  of  1£  Ibs.  to  150  gal.  of 
water.  Two  died  the  third,  two  the  fifth  and  one  the  sixth 
day ;  one  died  and  one  pupated  the  seventh  day ;  two  died 
the  eighth  and  one  the  ninth  day. 

Check  experiment :  one  died  the  ninth  day. 

No.  56.  —June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed  with 
arsenate  of  lead,  in  the  proportion  of  1£  Ibs.  to  150  gal.  of 
water.  One  died  the  first,  one  the  second,  two  the  third, 
two  the  fourth,  two  the  fifth  and  two  the  seventh  day. 

Check  experiment :  one  pupated  the  second  day ;  cine  died 
the  fourth  and  one  the  sixth  day. 

No.  57  (field  experiment). — June  24,  1893.  An  apple- 
tree  branch  was  sprayed  with  arsenate  of  lead,  in  the  pro- 
portion of  1£  Ibs.  to  150  gal.  of  water,  and  nine  fourth-molt 
caterpillars  placed  upon  it.  Two  died  before  pupating,  and, 
of  the  seven  that  pupated,  one  died  without  emerging. 
Foliage  uninjured. 

No.  58.— July  9,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed  with 
arsenate  of  lead,  in  the  proportion  of  1£  Ibs.  to  150  gal. 
of  water.  One  died  and  one  pupated  the  fourth  day ;  one 
died  and  one  pupated  the  fifth  day  ;  two  died  the  sixth  and 
one  the  seventh  day ;  one  pupated  the  ninth  day ;  two  died 
the  eleventh  day. 


INSECTICIDES.  459 

Check  experiment :  three  pupated  the  fourth  and  two  the 
fifth  day  ;  one  died  and  one  pupated  the  seventh  day ;  one 
died  the  eighth  day ;  and  two  were  living  at  the  close  of  the 
experiment. 

No.  59  (field  experiment). —July  9,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  arsenate  of  lead,  in  the  pro- 
portion of  1£  Ibs.  to  150  gal.  of  water.  One  died  the  fifth 
day  ;  one  pupated  the  eleventh  and  one  the  twelfth  day,  one 
died  the  fourteenth  day ;  one  pupated  the  fifteenth  day,  one 
died  the  sixteenth  day  ;  one  pupated  the  eighteenth,  one  the 
twentieth,  one  the  twenty-first  and  one  the  twenty-fourth  day. 

No.  60  (field  experiment). — June  24,  1893.  A  branch 
of  apple  tree  was  sprayed  with  arsenate  of  lead,  in  the  pro- 
portion of  1£  Ibs.  to  150  gal.  of  water,  and  ten  fifth-molt 
caterpillars  placed  upon  it.  July  10,  one  caterpillar  having 
pupated  and  been  removed,  those  remaining  were  transferred 
to  a  freshly  sprayed  apple  branch.  Only  four  of  the  ten 
which  pupated  emerged.  Foliage  uninjured. 

2  Ibs.  Arsenate  of  Lead  to  150  gal.  Water. 

No.  61.  — March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  2  Ibs.  to  150  gal. 
of  water.  One  died  the  first,  four  the  fourth,  two  the  fifth 
and  two  the  sixth  day ;  and  one  was  lost. 

No.  62. — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  2  Ibs.  to  150  gal.  of 
water.  On  the  fifth  day  five  were  dead ;  two  died  the  sixth 
and  three  the  seventh  day. 

Check  experiment :  none  dead. 

Xo.  63. — May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  2  Ibs.  to  150  gal. 
of  water.  On  the  fourth  day  two  died;  on  the  fifth,  three  ; 
on  the  sixth,  two  ;  on  the  seventh,  one  ;  on  the  eighth,  one  ; 
and  on  the  eleventh,  one. 

Check  experiment :  one  died  the  sixth  day. 

Xo.  64.  —  June  10,  1894.    Ten  caterpillars,  of  the  second 


460  THE   GYPSY  MOTH. 

molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  2  Ibs.  to  150  gal. 
of  water.  One  died  the  second,  three  the  fourth,  three  the 
fifth,  one  the  sixth,  one  the  seventh  and  one  the  tenth  day. 

Check  experiment :  none  dead. 

No.  65.  — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  2  Ibs.  to  150  gal. 
of  water.  Four  died  the  third,  three  the  fourth,  two  the 
sixth  and  one  the  seventh  day. 

Check  experiment:  one  lost  the  seventh  and  one  the 
eighth  day. 

No.  66.  —June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  2  Ibs.  t6  150  gal. 
of  water.  Two  died  the  fourth,  four  the  fifth,  two  the  sixth 
and  two  the  seventh  day. 

Check  experiment :  one  died  and  two  pupated  the  second 
day ;  two  died  the  third  day,  two  the  fourth  and  three  the 
fifth  day. 

No.  67  (field  experiment).— June  21,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  2  Ibs.  to  150  gal.  of  water,  and  ten  fourth- 
molt  caterpillars  placed  upon  it.  Four  of  these  caterpillars 
began  to  pupate,  and,  as  the  food  gave  out,  those  remaining 
were  transferred  to  a  branch  which  had  not  been  sprayed, 
two  more  pupating  after  their  removal.  The  other  four  cater- 
pillars died  from  the  effects  of  the  poison.  Foliage  uninjured. 

No.  68  (field  experiment). — June  24,  1893.  A  branch 
of  apple  tree  was  sprayed  with  arsenate  of  lead,  in  the  pro- 
portion of  2  Ibs.  to  150  gal.  of  water,  and  eight  fourth-molt 
caterpillars  placed  upon  it.  On  account  of  the  rain,  the 
branch  was  resprayed  twice.  One  caterpillar  pupated,  and 
from  the  pupa  a  male  moth  emerged.  The  rest  were  all 
dead  by  the  9th  of  August.  Foliage  uninjured. 

No.  69  (field  experiment). —June  24,  1893.  A  branch 
of  apple  tree  was  sprayed  with  arsenate  of  lead,  in  the  pro- 
portion of  2  Ibs.  to  150  gal.  of  water,  and  nine  fourth-molt 
caterpillars  placed  upon  it.  Five  of  the  caterpillars  died 
before  pupating,  and,  of  the  four  that  pupated,  three  emerged. 


INSECTICIDES.  461 

The  poison  acted  very  slowly,  as  none  of  the  caterpillars 
died  for  nearly  three  weeks,  and  one  lived  eight  weeks. 

No.  70.— July  9,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  2  Ibs.  to  150  gal. 
of  water.  One  died  the  second  day ;  three  died  and  one 
pupated  the  fifth  day ;  one  died  and  one  pupated  the  sixth 
and  seventh  days ;  and  one  pupated  the  tenth  day. 

Check  experiment :  two  pupated  the  fourth,  three  the  fifth, 
one  the  sixth,  seventh  and  eighth  days ;  and  two  were  living 
at  the  close  of  the  experiment. 

No.  71  (field  experiment).— July  9,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  arsenate  of  lead,  in  the  propor- 
tion of  2  Ibs.  to  150  gal.  of  water.  One  died  the  first  day ; 
one  pupated  the  third  day ;  one  died  the  fourth  and  one  the 
fifth  day ;  one  pupated  the  eighth  and  one  the  twelfth  day ; 
one  died  and  one  pupated  the  thirteenth  day ;  one  pupated 
the  fifteenth  and  one  the  eighteenth  day. 

No.  72  (field  experiment). — June  21,  1893.  A  branch 
of  a  small  hop-hornbeam  was  sprayed  with  arsenate  of  lead, 
in  the  proportion  of  2  Ibs.  to  150  gal.  of  water,  and  ten  fifth- 
molt  caterpillars  were  placed  upon  it.  July  14,  all  were 
dead.  In  this  experiment  the  caterpillars  died  gradually, 
the  first  one  dying  two  days  after  the  poison  had  been 
applied,  the  last  one  living  twenty-two  days.  The  foliage 
of  the  tree  was  uninjured. 

No.  73  (field  experiment) .— June  24,,  1893.  A  branch 
of  apple  tree  was  sprayed  with  arsenate  of  lead,  in  the  pro- 
portion of  2  Ibs.  to  150  gal.  of  water,  and  nine  fifth-molt 
caterpillars  placed  upon  it.  In  this  experiment  the  poison 
was  nearly  all  washed  off  by  heavy  rains  soon  after  it  was 
applied.  Four  of  the  caterpillars  molted  and  two  pupated, 
but  all  were  dead  August  2.  Foliage  uninjured. 

No.  74  (field  experiment). — June  24,  1893.  A  branch 
of  apple  tree  was  sprayed  with  arsenate  of  lead,  in  the  pro- 
portion of  2  Ibs.  to  150  gal.  of  water,  and  nine  fifth-molt 
caterpillars  placed  upon  it.  Six  of  the  nine  caterpillars  died 
before  pupating,  and,  of  the  three  which  pupated,  only  one 
emerged.  Foliage  uninjured. 


462  THE   GYPSY  MOTH. 

No.  75  (field  experiment) .— July  7,  1893.  A  branch 
of  oak  was  sprayed  with  arsenate  of  lead,  in  the  proportion 
of  2  Ibs.  to  150  gal.  of  water,  and  ten  caterpillars,  of  the  fifth 
molt,  placed  upon  it.  On  July  22,  and  also  on  the  27th,  the 
branch  was  resprayed  on  account  of  rain.  In  this  experi- 
ment only  one  caterpillar  began  pupating,  and  that  one  was 
not  able  to  complete  the  process. 

No.  76  (field  experiment). — July  7,  1893.  A  branch 
of  oak  was  sprayed  with  arsenate  of  lead,  in  the  proportion 
of  2  Ibs.  to  150  gal.  of  water,  and  ten  fifth-molt  caterpillars 
placed  upon  it.  Three  of  these  began  pupating,  and  one 
emerged ;  but,  as  this  one  began  to  pupate  very  soon  after 
the  poison  was  applied,  it  probably  did  not  get  any  ill  effect 
from  it.  Foliage  uninjured. 

3  Ibs.  Arsenate  of  Lead  to  150  gal.  Water. 

No.  77.  —  March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  3  Ibs.  to  150  gal. 
of  water.  Six  died  the  third,  one  the  fourth  and  three  the 
sixth  day. 

No.  78.  — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  3  Ibs.  to  150  gal.  of 
water.  One  died  the  third,  three  the  fourth,  two  the  fifth, 
one  the  sixth  and  one  the  seventh  day ;  the  remainder  sur- 
vived. 

Check  experiment :  none  dead. 

No.  79.— May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  3  Ibs.  to  150  gal. 
of  water.  Two  died  the  fourth,  one  the  fifth,  two  the  sixth, 
one  the  seventh,  three  the  eighth  and  one  the  ninth  day. 

Check  experiment :  one  died  the  sixth  day. 

No.  80.  — June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  3  Ibs.  to  150  gal. 
of  water.  One  died  the  fourth,  eight  the  fifth  and  one  the 
sixth  day. 

Check  experiment :  none  dead. 


INSECTICIDES.  463 

No.  81. — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  3  Ibs.  to  150  gal. 
of  water.  Three  died  the  fourth,  five  the  sixth  and  two  the 
seventh  day. 

Check  experiment :  one  died  the  seventh  day. 

No.  82. — June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  3  Ibs.  to  150  gal. 
of  water.  Two  died  and  one  pupated  the  second  day ;  two 
died  the  third,  two  the  fourth  and  three  the  fifth  day. 

Check  experiment :  two  pupated  the  second  and  one  the 
fifth  day. 

Xo.  83  (field  experiment). — June  30,  1893.  A  branch 
of  a  small  oak  tree  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  3  Ibs.  to  150  gal.  of  water,  and  seven  fourth- 
molt  caterpillars  placed  upon  it.  The  branch  was  resprayed 
July  20,  on  account  of  rain.  All  of  these  caterpillars  died 
within  twenty-five  days  after  the  first  spraying,  and  five  days 
after  the  second.  Foliage  uninjured. 

No.  84  (field  experiment). — June  30,  1893.  A  branch 
of  oak  was  sprayed  with  arsenate  of  lead,  in  the  proportion 
of  3  Ibs.  to  150  gal.  of  water,  and  eight  fourth-molt  cater- 
pillars placed  upon  it.  August  27,  all  were  dead.  Foliage 
uninjured. 

Js'o.  85. — July  9,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  leaves  which  had  been  sprayed  with 
arsenate  of  lead,  in  the  proportion  of  3  Ibs.  to  150  gal.  of 
water.  One  died  and  one  pupated  the  third  day;  one 
pupated  the  sixth  day :  three  died  the  seventh  day ;  one  died 
and  two  pupated  the  ninth  day ;  and  one  pupated  the  thir- 
teenth day. 

Check  experiment :  one  pupated  the  fourth,  fifth  and  sixth 
days :  one  died  the  seventh  day ;  one  pupated  the  eighth  and 
two  the  ninth  day  ;  and  one  died  the  eleventh  day. 

No.  86  (field  experiment). — July  9,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  arsenate  of  lead,  in  the  propor- 
tion of  3  Ibs.  to  150  gal.  of  water.  One  died  the  first  and 
one  the  second  day  ;  one  pupated  the  fifth,  two  the  sixth  and 


464  THE  GYPSY  MOTH. 

two  the  eighth  day;  one  died  the  fourteenth  day;  one 
pupated  the  twenty-fifth  and  one  the  twenty-eighth  day. 

No.  87  (field  experiment). — June  30,  1893.  A  branch 
of  oak  was  sprayed  with  arsenate  of  lead,  in  the  proportion 
of  3  Ibs.  to  150  gal.  of  water,  and  ten  caterpillars  of  the  fifth 
molt  placed  upon  it.  All  died  within  three  weeks,  and  six 
of  the  ten  in  less  than  one  week  after  the  branch  was  sprayed. 
Foliage  uninjured. 

No.  88  (field  experiment) .— June  30,  1893.  A  branch 
of  oak  was  sprayed  with  arsenate  of  lead,  in  the  proportion 
of  3  Ibs.  to  150  gal.  of  water,  and  ten  caterpillars  of  the  fifth 
molt  placed  upon  it.  July  20,  the  branch  was  resprayed  on 
account  of  rain.  Only  two  of  these  caterpillars  pupated  and 
but  one  emerged.  Foliage  uninjured. 

4  Ibs.  Arsenate  of  Lead  to  150  gal.  Water. 

No.  89.— March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  4  Ibs.  to  150  gal. 
of  water.  Three  died  the  third,  two  the  fourth  and  five  the 
fifth  day. 

No.  90.  — May  9,  1895.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  4  Ibs.  to  150  gal.  of 
water.  One  died  the  third,  two  the  fourth,  five  the  fifth  and 
two  the  sixth  day. 

Check  experiment :  none  dead. 

No.  91.— May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  4  Ibs.  to  150  gal. 
of  water.  Two  died  the  third,  three  the  fourth,  two  the 
fifth  and  three  the  seventh  day. 

Check  experiment :  none  dead. 

No.  92.  —June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  4  Ibs.  to  150  gal. 
of  water.  One  died  the  second,  one  the  third,  one  the 
fourth,  two  the  fifth,  one  the  sixth,  two  the  seventh  and  two 
the  eighth  day. 

Check  experiment :  none  dead. 


INSECTICIDES.  465 

No.  93.— June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  4  Ibs.  to  150  gal. 
of  water.  One  died  the  third,  one  the  fourth,  two  the  fifth, 
three  the  sixth  and  three  the  seventh  day. 

Check  experiment :  one  died  the  seventh  day. 

No.  94. — June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  4  Ibs.  to  150  gal. 
of  water.  One  died  the  second,  five  the  third,  two  the 
fourth,  one  the  fifth  and  one  the  sixth  day. 

Check  experiment :  one  pupated  and  one  died  the  second 
day ;  one  pupated  the  third  day ;  and  one  died  the  fifth  day. 

No.  95  (field  experiment). — June  21,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  4  Ibs.  to  150  gal.  of  water,  and  ten  fourth-molt 
caterpillars  placed  upon  it.  In  this  experiment  eight  of  the 
ten  caterpillars  died  within  nine  days ;  the  other  two  lived 
twelve  and  thirteen  days  longer.  Foliage  uninjured. 

No.  96.  —July  9,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  4  Ibs.  to  150  gat. 
of  water.  One  pupated  and  two  died  the  fourth  day,  two 
pupated  and  three  died  the  fifth  day ;  one  died  the  sixth  and 
one  the  seventh  day. 

Check  experiment :  one  died  the  fourth  day. 

No.  97  (field  experiment). — July  9,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  arsenate  of  lead,  in  the  propor- 
tion of  4  Ibs.  to  150  gat.  of  water.  One  died  and  one 
pupated  the  third  day ;  one  died  the  fifth  and  one  the  sixth 
day ;  one  pupated  the  seventh  and  one  the  ninth  day ;  one 
died  the  eleventh  day ;  one  pupated  the  twelfth  day ;  one 
died  the  fifteenth  day  ;  one  pupated  the  twent3^-mnth  day. 

No.  98  (field  experiment). — June  21,  1893.  A  branch 
of  hop-hornbeam  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  4  Ibs.  to  150  gal.  of  water,  and  ten  fifth-molt 
caterpillars  placed  upon  it.  July  12,  all  were  dead.  Al- 
though these  were  fifth-molt  caterpillars,  they  succumbed  to 
the  poison  much  quicker  than  those  of  the  fourth  molt,  six 


466  THE   GYPSY  MOTH. 

dying  within  a  week,  and  the  last  one  dying  in  a  little  over 
two  weeks.     Foliage  uninjured. 

5  Ibs.  Arsenate  of  Lead  to  150  gal  Water. 

No.  99.— March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  5  Ibs.  to  150 
gal.  of  water.  One  died  the  first,  two  the  third,  one  the 
fourth,  four  the  fifth,  and  one  died  and  one  was  lost  the  sixth 
day. 

No.  100.— May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  5  Ibs.  to  150  gal.  of 
water.  Four  died  the  third,  three  the  fourth  and  three  the 
fifth  day. 

Check  experiment :  none  dead. 

No.  101.  —May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  5  Ibs.  to  150  gal. 
of  water.  Three  died  the  fourth,  one  the  fifth,  four  the  sixth 
and  two  the  seventh  day. 

Check  experiment :  none  dead. 

No.  102.— June  10,  1894.  Ten  caterpillars,  of  the 
second  molt,  were  placed  on  lettuce  leaves  which  had  been 
treated  with  arsenate  of  lead,  in  the  proportion  of  5  Ibs.  to 
150  gal.  of  water.  Two  died  the  second,  three  the  fifth,  one 
the  sixth,  three  the  seventh  and  one  the  ninth  day. 

Check  experiment :  none  dead. 

No.  103.  — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  5  Ibs.  to  150  gal. 
of  water.  Two  died  the  third,  two  the  fourth,  one  the  fifth 
and  five  the  sixth  day. 

Check  experiment :  none  dead. 

No.  104. — June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  5  Ibs.  to  150  gal.  of 
water.  Three  died  the  second,  two  the  third,  two  the 
fourth,  one  the  fifth  and  two  the  sixth  day. 

Check  experiment :  one  died  and  two  pupated  the  second 


INSECTICIDES.  467 

day ;  one  pupated  the  third  day ;  two  died  the  fourth  and 
one  the  fifth  day. 

No.  105  (field  experiment). — June  21,  1893.  A  branch 
of  oak  was  sprayed  with  arsenate  of  lead,  in  the  proportion 
of  5  Ibs.  to  150  gal.  of  water,  and  ten  fourth-molt  caterpillars 
placed  upon  it.  July  5,  the  last  one  was  dead.  In  this 
experiment  five  or  six  days  were  required  for  the  poison  to 
take  effect ;  after  that  time,  however,  the  caterpillars  died 
rapidly. 

No.  106.— July  9,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  5  Ibs.  to  150  gal. 
of  water.  One  pupated  the  third  day ;  one  died  the  fourth 
and  one  the  fifth  day ;  one  pupated  and  one  died  the  sixth 
day ;  two  died  the  seventh  and  one  the  eighth,  twelfth  and 
thirteenth  days. 

Check  experiment :  one  died  the  third  day ;  one  pupated 
the  fifth  day ;  two  died  the  sixth  and  one  the  seventh  day ; 
one  died  and  one  pupated  the  eleventh  day ;  one  pupated 
the  twelfth  day. 

No.  107  (field  experiment). — July  9,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  treated  with  arsenate  of  lead,  in  the  propor- 
tion of  5  Ibs.  to  150  gal.  of  water.  One  died  and  one 
pupated  the  fourth  day ;  two  died  the  eleventh  and  two  the 
twelfth  day  ;  one  pupated  the  seventeenth,  one  the  nineteenth 
and  two  the  twentieth  day. 

6  Ibs.  Arsenate  of  Lead  to  150  gal.  Water. 

No.  108. — March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  6  Ibs.  to  150  gal. 
of  water.  One  died  the  first,  one  the  second,  three  the  third, 
four  the  fourth  and  one  the  fifth  day. 

No.  109.  — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  6  Ibs.  to  150  gal.  of 
water.  Two  died  the  first,  five  the  third  and  three  the  fifth 
day. 

Check  experiment :  none  dead. 


468  THE   GYPSY   MOTH. 

No.  110. — May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  6  Ibs.  to  150  gal. 
of  water.  Two  died  the  third,  one  the  fourth,  two  the  fifth, 
two  the  sixth  and  three  the  eighth  day. 

Check  experiment :  one  died  the  sixth  day. 

No.  111.  —June  10,  1894.  Ten  caterpillars,  of  the  second 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  6  Ibs.  to  150  gal. 
of  water.  One  died  the  third,  two  the  fourth,  three  the  fifth, 
three  the  sixth  and  one  the  eighth  day. 

Check  experiment :  none  dead. 

No.  112.  — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  6  Ibs.  to  150  gal. 
of  water.  One  died  the  second,  three  the  third,  two  the 
fourth,  one  the  fifth,  two  the  sixth  and  one  the  seventh  day. 

Check  experiment :  none  dead. 

No.  113.  —June  29,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  6  Ibs.  to  150  gal. 
of  water.  Three  died  the  second,  two  the  third,  three  the 
fourth  and  two  the  sixth  day. 

Check  experiment :  one  died  and  one  pupated  the  second 
day ;  one  died  the  third  and  one  the  fifth  day. 

No.  114  (field  experiment).  — July  1,  1893.  A  branch 
of  a  small  oak  tree  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  6  Ibs.  to  150  gal.  of  water,  and  ten  large  fifth- 
molt  caterpillars  placed  upon  it.  All  died  within  three 
weeks  from  the  time  of  spraying.  Foliage  uninjured. 

No.  115.— July  9,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  6  Ibs.  to  150  gal. 
of  water.  Two  died  and  three  pupated  the  fourth  day; 
three  died  the  seventh,  one  the  ninth  and  one  the  tenth  day. 

Check  experiment :  one  died  and  two  pupated  the  fourth 
day  ;  one  died  the  fifth  day  ;  two  pupated  the  sixth  and  one 
the  seventh  and  eighth  days. 

No.  116  (field  experiment). — July  9,  1894.     Ten  cater- 


INSECTICIDES.  469 

pillars,  of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  treated  with  arsenate  of  lead,  in  the  propor- 
tion of  6  Ibs.  to  150  gal.  of  water.  One  died  the  second 
day  ;  one  pupated  the  third  day ;  two  died  the  fifth,  two  the 
sixth  and  one  the  eleventh  day ;  one  pupated  the  thirteenth, 
one  the  sixteenth  and  one  the  nineteenth  day. 

7  Ibs.  Arsenate  of  Lead  to  150  gal.  Water. 

No.  117. — March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  7  Ibs.  to  150  gal. 
of  water.  Three  died  the  first,  three  the  second  and  four 
the  fifth  day. 

No.  118. — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  7  Ibs.  to  150  gal.  of 
water.  One  died  the  second,  five  the  third,  two  the  fourth, 
one  the  fifth  and  one  the  seventh  day. 

Check  experiment :  none  dead. 

No.  119.— May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  7  Ibs.  to  150  gal. 
of  water.  Five  died  the  third,  one  the  fourth,  two  the  sixth 
and  two  the  seventh  day. 

Check  experiment :  one  died  the  fourth  day. 

No.  120. — June  10,  1894.  Ten  caterpillars,  of  the 
second  molt,  were  placed  on  elm  leaves  which  had  been 
sprayed  with  arsenate  of  lead,  in  the  proportion  of  7  Ibs.  to 
150  gal.  of  water.  One  died  the  fourth,  one  the  fifth,  seven 
the  sixth  and  one  the  ninth  day. 

Check  experiment :  none  dead. 

No.  121.  — June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  7  Ibs.  to  150  gal. 
of  water.  One  died  the  second,  four  the  third,  four  the 
sixth  and  one  the  seventh  day. 

Check  experiment :  none  dead. 

No.  122.  — June  28,  1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 


470  THE   GYPSY  MOTH. 

with  arsenate  of  lead,  in  the  proportion  of  7  Ibs.  to  150  gal. 
of  water.  One  died  the  first,  one  the  second,  five  the  fourth 
and  three  the  fifth  day. 

Check  experiment :  two  pupated  the  second  and  three  the 
third  day ;  two  died  the  fifth  day. 

No.  123.  — July  9,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  7  Ibs.  to  150  gal. 
of  water.  One  pupated  the  third  day  ;  three  died  and  one 
pupated  the  fifth  day ;  one  died  the  seventh,  one  the  eighth, 
two  the  ninth  and  one  the  twelfth  day. 

Check  experiment :  two  pupated  the  fifth  day ;  one  died 
the  seventh,  ninth  and  tenth  days. 

No.  124. — July  9,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  willow  branches  which  had  been 
sprayed  with  arsenate  of  lead,  in  the  proportion  of  7  Ibs.  to 
150  gal.  of  water.  One  pupated  the  second  day ;  one  died 
the  third,  one  the  fifth,  one  the  sixth,  one  the  eighth  and 
one  the  tenth  day ;  one  died  and  one  pupated  the  eleventh 
day ;  one  pupated  the  sixteenth  and  one  the  thirty-first  day. 

8  Ibs.  Arsenate  of  Lead  to  150  gal.  Water. 

No.  125.  —March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  8  Ibs.  to  150  gal. 
of  water.  Three  died  the  second,  four  the  third  and  three 
the  fifth  day. 

No.  126.  — May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  8  Ibs.  to  150  gal.  of 
water.  Two  died  the  third,  three  the  fourth,  four  the  fifth 
and  one  the  sixth  day. 

Check  experiment :  none  dead. 

No.  127.— May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  8  Ibs.  to  150  gal. 
of  water.  Two  died  the  third,  two  the  fourth,  two  the  fifth, 
three  the  sixth  and  one  the  seventh  day. 

Check  experiment :  none  dead. 

No.    128.  —  June   10,    1894.      Ten    caterpillars,    of  the 


INSECTICIDES.  471 

second  molt,  were  placed  on  lettuce  leaves  which  had  been 
sprayed  with  ar senate  of  lead,  in  the  proportion  of  8  Ibs.  to 
150  gal.  of  water.  Four  died  the  second,  two  the  fourth, 
one  the  fifth,  one  the  sixth  and  two  the  seventh  day. 

Check  experiment :  none  dead. 

No.  129.  —  June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  8  Ibs.  to  150  gal. 
of  water.  One  died  the  second,  three  the  third,  one  the 
fourth,  three  the  fifth  and  two  the  sixth  day. 

Check  experiment :  none  dead. 

No.  130.  —  June  29,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves,  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  8  Ibs.  to  150  gal. 
of  water.  One  died  the  second,  three  the  third,  four  the 
fourth  and  two  the  fifth  day. 

Check  experiment :  four  pupated  the  second,  one  the  third 
and  one  the  fifth  day. 

No.  131. — July  9,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  8  Ibs.  to  150  gal. 
of  water.  One  pupated  the  fourth  day ;  three  pupated  and 
two  died  the  fifth  day ;  two  pupated  the  seventh  day ;  one 
died  the  ninth  and  one  the  twelfth  day. 

Check  experiment :  one  pupated  the  fourth,  fifth,  seventh 
and  ninth  days. 

No.  132  (field  experiment). — July  9,  1894.  Ten  cater- 
pillars, of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  arsenate  of  lead,  in  the  propor- 
tion of  8  Ibs.  to  150  gal.  of  water.  One  died  the  third  and 
one  the  fourth  day ;  one  pupated  the  eighth  day ;  one  died 
the  thirteenth  day;  three  pupated  the  sixteenth,  two  the 
twentieth  and  one  the  twenty-second  day. 

10  Ibs.  Arsenate  of  Lead  to  150  gal.  Water. 
No.  133.  —  March  7,  1894.  Ten  caterpillars,  three  days 
old,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  10  Ibs.  to  150  gal. 
of  water.  Five  died  the  second,  four  the  third  and  one  the 
fourth  day. 


472  THE  GYPSY  MOTH. 

No.  134.— May  9,  1894.  Ten  caterpillars,  six  days  old, 
were  placed  on  lettuce  leaves  which  had  been  treated  with 
arsenate  of  lead,  in  the  proportion  of  10  Ibs.  to  150  gal.  of 
water.  Three  died  the  second,  two  the  third,  two  the  fourth 
and  three  the  fifth  day. 

Check  experiment :  none  dead. 

No.  135.— May  28,  1894.  Ten  caterpillars,  of  the  first 
molt,  were  placed  on  lettuce  leaves  which  had  been  treated 
with  arsenate  of  lead,  in  the  proportion  of  10  Ibs.  to  150  gal. 
of  water.  One  died  the  third,  three  the  fourth,  three  the 
fifth,  one  the  sixth  and  two  the  seventh  day. 

Check  experiment :  none  dead. 

No.  136.  —  June  10,  1894.  Ten  caterpillars,  of  the 
second  molt,  were  placed  on  lettuce  leaves  which  had  been 
sprayed  with  arsenate  of  lead,  in  the  proportion  of  10  Ibs.  to 
150  gal.  of  water.  Three  died  the  second,  one  the  third, 
one  the  fourth,  two  the  fifth,  two  the  sixth  and  one  the 
seventh  day. 

Check  experiment :  none  dead. 

No.  137.  —  June  21,  1894.  Ten  caterpillars,  of  the  third 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  10  Ibs.  to  150  gal. 
of  water.  Three  died  the  fourth,  four  the  sixth  and  three 
the  seventh  day. 

Check  experiment :  none  dead. 

No.  138.— June  29, 1894.  Ten  caterpillars,  of  the  fourth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  10  Ibs.  to  150  gal. 
of  water.  One  died  the  second,  three  the  third,  five  the 
fourth  and  one  the  fifth  day. 

Check  experiment :  one  pupated  the  second  and  one  the 
third  day ;  one  pupated  and  one  died  the  fifth  day. 

No.  139.— July  9,  1894.  Ten  caterpillars,  of  the  fifth 
molt,  were  placed  on  elm  leaves  which  had  been  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  10  Ibs.  to  150  gal. 
of  water.  Two  died  and  one  was  lost  the  fifth  day ;  four 
died  the  sixth  and  three  the  seventh  day. 

Check  experiment :  one  pupated  the  fourth,  two  the  fifth, 
one  the  sixth  and  one  the  seventh  day. 

No.  140  (field  experiment). — July  9,  1894.     Ten  cater- 


INSECTICIDES.  473 

pillars,  of  the  fifth  molt,  were  placed  on  willow  branches 
which  had  been  sprayed  with  arsenate  of  lead,  in  the  propor- 
tion of  10  Ibs.  to  150  gal.  of  water.  Two  died  the  second 
day ;  three  pupated  the  fourth  day ;  two  died  the  fifth  and 
one  the  sixth  day ;  one  pupated  the  thirteenth  and  one  the 
fifteenth  day. 

No.  141  (field  experiment). — June  21,  1893.  A  branch 
of  a  small  oak  tree  was  sprayed  with  arsenate  of  lead,  in  the 
proportion  of  10  Ibs.  to  150  gal.  of  water,  and  eight  fifth- 
molt  caterpillars  placed  upon  it.  August  19,  all  were  dead. 

25  Ibs.  Arsenate  of  Lead  to  150  gal.  Water. 

No.  142. — July  1,  1893.  A  small  branch  of  oak  was 
sprayed  with  arsenate  of  lead,  in  the  proportion  of  25  Ibs. 
to  150  gal.  of  water,  and  ten  large  fifth-molt  caterpillars 
placed  upon  it.  All  died  within  one  week.  Foliage  unin- 
jured. 

Even  larger  proportions  of  this  poison  than  the  above 
were  occasionally  used  in  spraying  operations  in  the  field, 
with  fairly  satisfactory  results. 

Comparative  Effects  of  Paris  Green,  Paris  Green  and  Lime 

and  Arsenate  of  Lead. 

A  careful  study  of  the  comparative  effect  of  equal  weights 
of  the  three  substances  used  in  the  preceding  experiments 
shows  that  there  is  practically  no  choice  between  Paris  green 
and  Paris  green  and  lime,  so  far  as  the  destruction  of  the  cater- 
pillars is  concerned.  The  largest  amount  of  these  poisons 
which  can  be  used  without  injuring  the  foliage  is  about  1  Ib. 
to  150  gat.  of  water,  and  at  this,  or  even  a  much  larger  rate, 
the  percentage  of  caterpillars  destroyed  is  not  satisfactory. 
Since  arsenate  of  lead  in  almost  any  strength  is  not  injurious 
to  foliage,  a  much  larger  amount  can  be  used  than  of  any  of 
the  more  soluble  arsenical  compounds ;  thus  the  superiority 
of  this  poison  as  an  insecticide  is  at  once  evident.  While 
arsenate  of  lead  may  be  considered  the  best  insecticide  for 
destroying  the  gypsy  moth  in  the  caterpillar  stage,  even  this 
poison  is  of  small  value  in  exterminating  this  insect,  since 
many  of  the  caterpillars  survive  after  feeding  upon  leaves 
sprayed  with  large  proportions  of  this  poison. 


474  THE  GYPSY  MOTH. 

The  experiments  previously  recorded  show  that  a  consid- 
erable amount  of  time  is  required  for  the  poison  used  to 
affect  the  caterpillars.  Those  in  the  earlier  molts  were 
killed  in  a  short  time,  but  in  the  later  molts  a  much  smaller 
per  cent,  was  destroyed,  many  of  the  caterpillars  transform- 
ing and  producing  imagoes. 

In  considering  these  experiments,  it  should  be  remem- 
bered that  the  insects  were  in  confinement,  and  obliged  to 
eat  the  poisoned  leaves,  while  in  field  work  they  may  some- 
times find  leaves  that  have  not  been  sprayed,  or  that  have 
received  but  little  of  the  poison,  and,  therefore,  the  results 
in  some  cases  might  be  somewhat  different  from  those 
obtained  in  these  experiments. 

The  remarkable  ability  of  the  gypsy  moth  to  resist  the 
action  of  arsenical  poisons  is  shown  in  the  case  of  other 
poisons.  Mr.  Moulton  covered  a  piece  of  lettuce  leaf  with 
strychnine,  and  fed  it  to  a  caterpillar.  In  about  an  hour  the 
caterpillar  appeared  to  be  dead,  but  soon  revived  and  fed 
again  for  a  short  time  upon  the  poisoned  leaf,  when  it  rolled 
over  on  its  back  and  for  several  hours  remained  apparently 
dead,  but  afterwards  revived  again  and  appeared  as  well  as 
ever. 

ANALYSES  OF  POISONED 


The  remarkable  resistance  to  the  action  of  arsenical 
poisons  shown  by  the  gypsy  moth  led  us,  in  the  summer 
of  1894,  to  institute  a  series  of  investigations  on  the  dis- 
position of  arsenic  by  caterpillars  when  feeding  on  poisoned 
food.  For  this  purpose,  gypsy  moth  caterpillars  which 
had  fed  for  some  time  upon  poisoned  leaves  without  ap- 
parent injury,  and  also  those  which  had  died  as  a  result 
of  arsenical  poisoning,  were  carefully  dissected,  the  differ- 
ent organs  and  tissues  being  subsequently  analyzed  at  the 
chemical  laboratory  of  Harvard  University.  The  work  was 
performed,  under  my  direction,  by  Messrs.  Kirkland  and 
Moulton,  the  former  preparing  the  material  and  making 
the  dissections,  the  latter  conducting  the  analyses.  All  the 
operations  involved  were  carried  on  with  extreme  care,  in 
order  to  prevent  the  accidental  introduction  of  any  arsenical 
substance.  After  each  dissection  the  instruments  used  were 


taken  Jn  Arlineton. 


ANALYSES  OF  POISONED  LARY^.          475 

carefully  washed  in  dilute  acid  and  in  distilled  water,  while 
the  purity  of  all  chemical  reagents  employed  in  the  analyti- 
cal work  was  demonstrated  by  a  number  of  preliminary 
tests.  The  method  used  in  testing  for  the  presence  of 
arsenic  was  the  so-called  Berzelius-Marsh  process  (Ameri- 
can Chemical  Journal,  "October,  1891),  by  means  of  which 
a  minute  quantity  of  this  poison  can  be  readily  recognized. 
The  results  obtained  from  analyses  of  the  organs  and  tissues 
of  a  large  number  of  caterpillars,  which  were  feeding  un- 
harmed on  food  treated  with  a  liberal  amount  of  Paris  green 
or  arsenate  of  lead  (the  only  poisons  used) ,  did  not  differ 
materially  from  those  of  analyses  of  the  same  parts  of  cater- 
pillars which  had  died  from  arsenical  poisoning,  while  in 
many  caterpillars  no  arsenic  was  found. 

In  both  cases  arsenic  was  found  chiefly  in  the  stomach, 
intestinal  and  rectal  contents,  and  throughout  the  walls  of 
the  alimentary  canal.  It  was  also  found  in  the  excrements, 
in  the  malpighian  vessels,  the  dorsal  vessel  and  blood  and 
in  the  muscular  tissue,  thus  showing  that  the  arsenic  prob- 
ably passes  from  the  alimentary  caftai,  where  it  is  quite 
equally  distributed,  into  the  blood,  and  is  carried  by  the 
circulation  throughout  the  body,  and  thus  eventually  per- 
meates all  organs  and  tissues.  Owing  to  the  small  size  of 
the  parts  subjected  to  analysis,  some  of  them  being  of  almost 
microscopic  dimensions,  it  was  an  extremely  difficult  process 
to  determine  quantitatively  the  amount  of  arsenic  present ; 
yet  this  was  accomplished  by  a  comparison  of  the  results 
of  the  analyses  with  a  series  of  finely  graduated  arsenic 
"mirrors,"  for  the  use  of  which  we  are  indebted  to  the 
courtesy  of  Professor  Hill  of  Harvard  University. 

In  some  caterpillars,  which  had  fed  for  a  long  time  upon 
food  treated  with  the  arsenical  compounds  previously  men- 
tioned, a  considerable  amount  of  arsenic  was  found ;  while 
those  which  had  fed  for  a  shorter  time,  as  a  rule,  contained 
smaller  quantities  of  the  poison.  Many  of  those  which  had 
thus  fed  for  two  or  three  weeks,  when  killed,  were  found  to 
contain  more  arsenic  than  caterpillars  which  had  succumbed 
to  arsenical  poisoning.  One  caterpillar,  which  had  fed  in 
an  out-door  cage,  upon  willow  leaves  sprayed  with  arsenate 


476  THE   GYPSY  MOTH. 

of  lead  in  the  proportion  of  2  Ibs.  to  150  gal.  of  water,  from 
July  9  to  July  28,  1894,  and  which  at  the  time  of  dissection 
was  fiill  grown,  normally  active  and  healthy,  yielded  .025 
milligrams  of  arsenic.  If,  for  the  purpose  of  illustration, 
the  weight  of  arsenic  thus  found  be  compared  with  the 
weight  of  this  caterpillar,  and  this  ratio  applied  to  the  aver- 
age weight  of  the  adult  human  being,  we  obtain  the  rather 
surprising  result  that  such  a  caterpillar  would  withstand 
uninjured  an  amount  of  arsenic,  in  proportion  to  its  weight, 
equivalent  to  twelve  and  one-half  times  the  fatal  dose  for  an 
adult  human  being,  in  proportion  to  the  weight  of  the  latter. 
This  illustrates  the  ability  of  this  insect  to  resist  arsenical 
poisoning. 

Since  the  quantities  of  arsenic  found  were  small  in  com- 
parison with  the  amount  the  insect  consumed,  it  is  evident 
that  a  considerable  part  of  the  poison  must  have  been 
eliminated  from  the  body.  The  presence  of  arsenic  in  the 
excrements  of  poisoned  caterpillars  indicates  one  source  of 
elimination.  These  investigations  upon  poisoned  cater- 
pillars show  that  an  apparently  large  quantity  of  arsenic 
may  enter  and  even  permeate  all  parts  of  the  body  of  the 
caterpillar  without  interfering  with  the  vital  processes,  and 
that  a  considerable  part  of  the  poison  consumed  with  the 
food  is  eliminated,  chiefly  in  the  excreta. 

One  interesting  result  obtained  from  the  analyses  of  the 
different  stages  of  the  gypsy  moth,  made  in  1893  and  1894, 
is  that  pupae  and  imagoes  from  caterpillars  which  have  been 
reared  on  leaves  sprayed  with  Paris  green  or  arsenate  of 
lead  may  contain  arsenic  in  recognizable  quantities.  Several 
pupae  and  a  few  female  imagoes,  obtained  under  these  con- 
ditions, when  subjected  to  chemical  analysis  gave  ample 
evidence  of  the  presence  of  arsenic  in  their  bodies.  This 
shows  that  the  presence  of  arsenic  in  the  pupa  may  not 
materially  interfere  with  the  processes  involved  in  the  de- 
velopment of  the  imago. 

Since,  as  has  been  repeatedly  demonstrated,  moths  reared 
from  poisoned  larvae  are  capable  of  reproduction,  it  is  also 
evident  that  the  arsenic  contained  in  their  systems  does  not 
injure  the  reproductive  function. 


INSECTICIDES.  477 


EXPERIMENTS    WITH    LONDON    PURPLE    AND    ACETATE    OP 
LEAD. 

No.  1. — July  7,  1893.  London  purple  and  acetate  of 
lead,  in  the  proportion  of  £  Ib.  each  to  150  gal.  of  water, 
were  thoroughly  mixed  and  allowed  to  stand  and  settle  for 
one  hour  and  a  half.  It  was  then  stirred  and  allowed  to 
stand  one-half  hour  longer,  at  the  end  of  which  time  it  was 
strained  through  two  thicknesses  of  cheese  cloth,  a  small 
amount  of  glucose  added,  and  an  oak  branch  sprayed  with 
the  mixture.  Ten  caterpillars,  of  the  fifth  molt,  were  then 
placed  upon  the  branch.  July  22,  for  lack  of  food,  they 
were  transferred  to  a  freshly  sprayed  branch.  None  of  these 
caterpillars  died  for  nearly  two  weeks  after  the  branch  was 
first  sprayed,  but  after  they  were  transferred  to  the  second 
sprayed  branch  they  died  more  rapidly.  Three  began  pu- 
pating, but  none  emerged.  The  foliage  of  the  first  branch 
was  slightly  burned,  while  that  of  the  second  was  in  good 
condition. 

No.  2.  —  July  6,  1893.  A  branch  of  a  small  oak  tree 
was  sprayed  with  London  purple  and  acetate  of  lead,  in  the 
proportion  off  Ib.  each  to  150  gal.  of  water.  The  London 
purple  and  acetate  of  lead  were  mixed  in  a  little  water,  glu- 
cose added  and  thoroughly  stirred ;  the  rest  of  the  water  was 
then  added  and  the  mixture  thoroughly  stirred  again.  Ten 
fifth-molt  caterpillars,  five  very  large  and  five  small,  were 
then  placed  on  the  branch.  July  25,  the  branch  was  re- 
sprayed,  on  account  of  rain.  Two  of  these  caterpillars 
began  to  pupate,  but  none  emerged.  They  died  gradually, 
the  last  one  living  nearly  a  month.  Foliage  considerably 
burned. 

No.  3. — July  6,  1893.  A  branch  of  oak  was  sprayed 
with  London  purple  and  acetate  of  lead,  in  the  proportion 
of  1  Ib.  each  to  150  gal.  of  water.  The  London  purple  and 
acetate  of  lead  were  thoroughly  mixed  with  water  in  a 
beaker,  a  teaspoonful  of  glucose  was  added  and  the  mixture 
thoroughly  stirred.  Eleven  fifth-molt  caterpillars  were 
placed*  on  the  branch.  July  20,  the  branch  was  resprayed, 
on  account  of  rain.  Of  the  eleven  caterpillars,  only  two 


478  THE   GYPSY  MOTH. 

were  able  to  complete  the  process  of  pupation  and  emerge. 
Foliage  in  good  condition. 

No.  4. — July  6,  1893.  A  branch  was  sprayed  with  the 
same  mixture  and  at  the  same  time  as  in  the  preceding 
experiment,  and  ten  fourth-molt  caterpillars  placed  upon  it. 
Only  two  of  these  began  to  pupate,  and  both  died  without 
emerging.  Foliage  but  slightly,  if  at  all,  burned. 

No.  5.  —  July  6,  1893.  A  branch  of  a  small  oak  tree 
was  sprayed  with  the  same  mixture  as  in  the  preceding 
experiment,  and  at  about  the  same  time.  Ten  fifth-rmolt 
caterpillars,  some  of  which  were  very  large,  were  placed  on 
the  branch.  July  20,  the  branch  was  resprayed,  on  account 
of  rain.  Only  two  of  the  caterpillars  began  to  pupate,  one 
of  which  emerged.  The  remainder  died  on  the  twenty- 
fourth  day  after  the  first  spraying.  The  foliage  was  slightly 
burned. 

No.  6. — July  7,  1893.  A  branch  of  oak  was  sprayed 
with  1  Ib.  of  London  purple  and  2  Ibs.  acetate  of  lead  to 
150  gal.  of  water,  and  ten  fifth-molt  caterpillars  placed  upon 
it.  Of  these  ten,  only  one  began  to  pupate,  and  this  one 
died  before  completing  the  process.  Foliage  only  slightly 
burned. 

No.  7. — July  7,  1893.  A  branch  of  oak  was  sprayed 
with  London  purple  and  acetate  of  lead,  in  the  proportion 
of  2  Ibs.  each  to  150  gal.  of  water.  The  London  purple 
and  acetate  of  lead  were  thoroughly  mixed  in  a  beaker,  the 
proper  amount  of  glucose  added,  and,  after  being  stirred, 
the  mixture  was  poured  into  the  sprayer,  the  rest  of  the 
water  added  and  the  whole  mixed  together.  Ten  fifth-molt 
caterpillars,  five  large  and  five  small,  were  then  placed  ou 
the  branch.  July  20,  the  branch  was  resprayed,  on  account 
of  rain.  All  of  the  caterpillars  except  one  died  before 
beginning  to  pupate,  and  this  one  was  not  able  to  complete 
the  process.  Foliage  in  good  condition. 

No.  8. — July  8,  1893.  An  oak  branch  was  sprayed 
with  London  purple  and  acetate  of  lead,  in  the  proportion 
of  3  Ibs.  each  to  150  gal.  of  water.  A  teaspoonful  of  glu- 
cose was  added,  and  the  mixture  thoroughly  stirred.  Ten 
large  fifth-molt  caterpillars  were  placed  oil  the  branch.  All 


INSECTICIDES.  479 

but  one  of  these  died  before  pupating,  and  this  one  did  not 
emerge.  Foliage  slightly  burned. 

No.  9.  —  July  8,  1893.  A  branch  of  oak  was  sprayed 
with  the  same  mixture  and  at  the  same  time  as  in  the  pre- 
ceding experiment,  and  ten  fifth-molt  caterpillars  placed 
upon  it.  Only  one  of  these  pupated,  and  that  one  did  not 
emerge.  Foliage  slightly  burned. 

No.  10.  —  July  8,  1893.  A  branch  was  sprayed  at  the 
same  time  and  in  the  same  manner  as  in  the  preceding 
experiment,  and  ten  fifth-molt  caterpillars  placed  upon  it. 
July  22,  and  again  on  the  25th,  the  branch  was  resprayed, 
on  account  of  rain.  Six  of  the  ten  caterpillars  pupated, 
three  of  which  emerged.  The  foliage  was  somewhat  burned. 


No.  1.  —  July  22,  1893.  A  branch  of  oak  was  sprayed 
with  antinonnin,  in  the  proportion  of  3  Ibs.  to  150  gal.  of 
water,  and  fifteen  caterpillars  of  the  fifth  molt  placed  upon 
it.  July  24,  the  branch  was  resprayed,  on  account  of  rain. 
Six  of  the  caterpillars  pupated,  four  of  which  emerged.  Foli- 
age in  good  condition.  The  antinonnin,  when  sprayed  on 
the  leaves,  presents  a  bright  yellow,  glistening  appearance, 
and  badly  stains  everything  with  which  it  comes  in  contact. 
It  is  also  easily  washed  off  by  rain. 

No.  2.  —  July  24,  1893.  A  branch  of  oak  was  sprayed 
with  antinonnin,  in  the  proportion  of  3  Ibs.  to  150  gal.  of 
water,  and  ten  caterpillars  of  the  fifth  molt  placed  upon  it. 
Five  of  these  pupated,  three  of  which  finally  emerged.  Foli- 
age slightly  burned. 

No.  3.—  July  27,  1893.  A  branch  of  oak  was  sprayed 
with  antinonnin,  in  the  proportion  of  3  Ibs.  to  150  gal.  of 
water,  and  fifteen  caterpillars  of  the  fifth  molt  placed  upon 
it.  Two  of  these  died  before  beginning  to  pupate,  and  ten 
pupated  and  emerged.  Foliage  in  good  condition. 

No.  4.  —  July  24,  1893.  A  branch  of  hop-hornbeam  was 
sprayed  with  antinonnin,  in  the  proportion  of  3  Ibs.  to  150 
gal.  of  water,  and  ten  fifth-molt  caterpillars  placed  upon  it. 
Six  of  these  pupated  and  finally  emerged.  Foliage  quite 
badly  burned. 


480  THE   GYPSY  MOTH. 

No.  5. — July  27,  1893.  A  branch  of  oak  was  sprayed 
with  antinonnin,  in  the  proportion  of  3  Ibs.  to  150  gal.  of 
water,  and  ten  fifth-molt  caterpillars  placed  upon  it.  This 
experiment  was  started  too  late  to  be  of  any  great  value  as  a 
test  for  the  insecticide,  as  all  the  caterpillars  pupated  very 
soon  after  the  branch  was  sprayed,  so  that  probably  few  if 
any  of  them  ate  enough  of  the  poisoned  food  to  affect  them. 

ARSENATE  OF  ZINC. 

Prepared  in  the  same  manner  as  arsenate  of  lead,  by  sub- 
stituting a  soluble  zinc  salt  for  the  acetate  of  lead. 

No.  1. — July  11,  1893.  A  branch  of  oak  was  sprayed 
with  arsenate  of  zinc,  in  the  proportion  of  1£  Ibs.  to  150  gal. 
of  water,  and  ten  fifth-molt  caterpillars  placed  upon  it. 
July  22,  and  again  on  the  25th,  the  branch  was  resprayed, 
on  account  of  heavy  rains.  Three  of  the  caterpillars  began 
pupating,  but  none  emerged.  Foliage  badly  burned. 

No.  2. — July  11,  1893.  A  branch  of  oak  was  sprayed 
with  arsenate  of  zinc,  in  the  proportion  of  1^  Ibs.  to  150  gal. 
of  water,  and  five  large  and  five  small  caterpillars  placed 
upon  it.  July  22,  the  branch  was  resprayed,  on  account  of 
rain.  Six  of  the  caterpillars  pupated,  four  of  which  emerged ; 
two  of  these,  however,  began  to  pupate  before  they  had  time 
to  eat  much  of  the  poisoned  food.  Foliage  slightly  burned. 

No.  3. — July  10,  1893.  A  branch  of  oak  was  sprayed 
with  arsenate  of  zinc,  in  the  proportion  of  2  Ibs.  to  150  gal. 
of  water,  and  ten  large  fifth-molt  caterpillars  placed  upon  it. 
Six  of  these  began  pupating,  but  none  emerged.  Foliage 
badly  burned. 

No.  4. — July  10,  1893.  A  branch  of  oak  was  sprayed 
with  arsenate  of  zinc,  in  the  proportion  of  3  Ibs.  to  150  gal. 
of  water,  and  five  large  and  five  small  caterpillars  of  the 
fifth  molt  placed  upon  it.  July  22,  the  branch  was  resprayed, 
on  account  of  rain.  Five  of  the  ten  caterpillars  began  pu- 
pating, but  none  emerged.  Foliage  badly  burned. 

No.  5. — July  10,  1893.  A  branch  of  oak  was  sprayed 
with  arsenate  of  zinc,  in  the  proportion  of  3  Ibs.  to  150  gal. 
of  water,  and  ten  very  large  fifth-molt  caterpillars  placed 
upon  it.  July  20,  they  were  transferred  to  a  freshly  sprayed 


INSECTICIDES.  481 

branch,  which,  July  25,  was  resprayed  on  account  of  rain. 
Five  of  the  ten  pupated,  one  of  which  emerged.  Foliage 
badly  burned. 

No.  6.  —  July  10,  1893.  A  branch  of  oak  was  sprayed 
with  arsenate  of  zinc,  in  the  proportion  of  3  Ibs.  to  150 
gal.  of  water,  and  ten  fifth-molt  caterpillars  placed  upon  it. 
Five  of  these  began  pupating,  but  none  emerged.  Foliage 
badly  burned. 

No.  7.  —  July  6,  1893.  A  branch  of  oak  was  sprayed 
with  arsenate  of  zinc,  in  the  proportion  of  6  Ibs.  to  150  gal. 
of  water,  and  ten  fifth-molt  caterpillars  placed  upon  it.  At 
the  end  of  two  weeks  all  were  dead.  Foliage  burned. 

No.  8. — July  6,  1893.  A  branch  of  oak  was  sprayed 
with  arsenate  of  zinc,  in  the  proportion  of  6  Ibs.  to  150  gal. 
of  water,  and  ten  fifth-molt  caterpillars  placed  upon  it.  All 
but  one  died  within  a  week,  and  this  one  died  eleven  days 
after  the  branch  was  sprayed.  Foliage  burned. 

ARSENIC. 

No.  1.  — July  12,  1893.  A  branch  of  oak  was  sprayed 
with  arsenic,  in  the  proportion  of  6  Ibs.  to  150  gal.  of  water, 
and  ten  caterpillars  of  the  fifth  molt  placed  upon  it.  July 
19,  the  branch  was  resprayed,  on  account  of  rain,  and  again 
on  the  25th.  Of  the  ten  caterpillars,  six  began  pupating, 
one  of  which  pupated  and  emerged.  Foliage  badly  burned. 

No.  2. — July  12,  1893.  A  branch  of  hop-hornbeam  was 
sprayed  with  arsenic,  in  the  proportion  of  6  Ibs.  to  150  gal. 
of  water,  and  ten  caterpillars  of  the  fifth  molt  placed  upon 
it.  July  19,  the  foliage  was  so  badly  burned  that  the  cater- 
pillars were  transferred  to  a  freshly  sprayed  branch  of  oak. 
Only  one  began  pupating,  and  this  one  did  not  emerge. 
Foliage  of  hop-hornbeam  very  badly  burned,  while  that  of 
the  oak  was  in  good  condition. 

"  CHLORO-XAPTHOLEUM." 

No.  1.  —  May  15,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  on  a  leaf  which  had  been  sprayed 
with  chloro-naptholeum.  At  the  end  of  seven  days,  all  the 
caterpillars  but  one  were  alive  and  in  good  condition. 


482  THE   GYPSY   MOTH. 

No.  2. — May  15,  1894.  Ten  caterpillars,  before  the  first 
molt,  were  placed  on  a  leaf  and  sprayed  with  chloro-naptho- 
leurn.  One  died  on  the  fifth  and  one  on  the  eighth  day ; 
those  remaining  seemed  in  good  condition. 

No.  3.  —  May  15,  1894.  Ten  caterpillars  were  placed  in 
a  dish  and  sprayed  with  chloro-naptholeum,  and  then  placed 
on  a  fresh  leaf.  Fresh  leaves  for  food  were  given  them  at 
four  different  times.  One  died  on  the  fourth  day  and  one  on 
the  sixth  day;  those  remaining  were  in  good  condition. 
The  strength  of  the  chloro-naptholeum  used  in  this  trial  was 
in  the  proportion  of  1  Ib.  to  100  gal.  of  water.  As  this 
neither  killed  the  caterpillars  nor  burned  the  leaves,  it  was 
repeated  with  a  stronger  solution. 

No.  4.  —May  22,  1894.  Ten  caterpillars,  before  the  first 
molt,  were  placed  on  a  leaf  which  had  been  sprayed  with 
chloro-naptholeum.  One  died  on  the  fifth,  two  on  the  sixth, 
two  on  the  seventh,  two  on  the  eighth  and  one  on  the  ninth 
day ;  the  remaining  two  were  alive  and  in  good  condition 
at  the  end  of  thirteen  days. 

Xo.  5.  — May  22,  1894.  Ten  caterpillars,  before  the  first 
molt,  were  placed  on  a  leaf  and  both  sprayed  with  chloro- 
naptholeum.  One  died  on  the  fourth,  three  on  the  sixth 
and  six  on  the  eighth  day. 

No.  6.  —May  22,  1894.  Ten  caterpillars,  before  the  first 
molt,  were  placed  in  a  dish  and  sprayed  with  chloro-nap- 
tholeum, and  then  placed  on  a  fresh  leaf.  Three  died  on 
the  third,  one  on  the  fourth,  three  on  the  fifth  and  three  on 
the  sixth  day.  The  strength  of  the  chloro-naptholeum  used 
in  this  trial  was  in  the  proportion  of  1  Ib.  to  50  gal.  of 
water. 

' '  ELECTRIC  "  INSECTICIDE. 

No.  1.  —  June  22,  1894.  A  leaf  was  sprayed  with  elec- 
tric insecticide,  and  ten  caterpillars,  of  the  second  molt, 
placed  upon  it.  Six  died  on  the  second  and  four  on  the 
third  day.  The  leaf  was  badly  burned. 

No.  2. — July  22,  1894.  Ten  second-molt  caterpillars 
were  placed  on  a  leaf  and  sprayed  with  electric  insecticide. 
All  died  on  the  second  day.  Leaf  badly  burned. 

No.  3.  —  June  2,  1894.     Ten  caterpillars,  of  the  second 


INSECTICIDES.  483 

molt,  were  dipped  in  electric  insecticide  and  then  placed  on 
a  fresh  leaf.  Nine  died  on  the  second  and  one  on  the  third 
day.  The  leaf  was  burned  by  contact  with  the  caterpillars. 

"ELPHONA." 

No.  1. — May  15,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  upon  a  leaf  which  had  been  sprayed 
with  Elphona.  On  the  third  day  all  were  dead. 

No.  2.— May  15,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  on  a  leaf  and  sprayed  with  Elphona. 
Four  died  on  the  third,  three  on  the  fourth  and  three  on  the 
fifth  day. 

No.  3. — May  15,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  in  a  dish  and  sprayed  with  Elphona. 
Nine  died  on  the  first  and  one  on  the  second  day.  Foliage 
badly  burned. 

These  three  insecticides,  " Chloro-naptholeuni,"  "Elec- 
tric "  and  "  Elphona,"  were  sent  to  the  department  by  their 
manufacturers  with  the  claim  that  they  would  kill  the  gypsy 
moth,  but  experiments  with  them  proved  that  when  used  in 
proportion  sufficiently  large  to  destroy  the  caterpillars  they 
burned  the  foliage  very  seriously. 

"HYANNIS  TOBACCO  MIXTURE"  (A  CONTACT  INSECTICIDE 
WITH  TOBACCO  AS  A  BASIS). 

No.  1. — May  15,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  on  a  leaf  which  had  been  sprayed 
with  Hyannis  tobacco  mixture.  One  died  on  the  fourth 
and  one  on  the  sixth  day. 

No.  2.— May  15,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  on  a  leaf  and  both  sprayed  with 
Hyannis  tobacco  mixture.  One  died  on  the  third,  three  on 
the  fifth,  one  on  the  sixth  and  two  on  the  seventh  day. 

No.  3. — May  15,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  in  a  dish  and  sprayed  with  Hyannis 
tobacco  mixture.  One  died  on  the  third,  three  on  the 
fourth  and  two  on  the  sixth  day.  The  strength  of  the 
Hyannis  tobacco  mixture  used  in  this  trial  was  in  the  pro- 
portion of  1  part  to  100  parts  of  water. 


484  THE   GYPSY  MOTH. 

No.  4. —May  22,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  on  a  leaf  which  had  been  sprayed 
with  Hyannis  tobacco  mixture.  Three  died  on  the  fourth, 
five  on  the  fifth  and  two  on  the  sixth  day. 

No.  5. — May  22,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  on  a  leaf  and  both  sprayed  with 
Hyannis  tobacco  mixture.  Seven  died  on  the  third,  two  on 
the  fourth  and  one  on  the  sixth  day. 

No.  6. — May  22,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  in  a  dish  and  sprayed  with  Hyannis 
tobacco  mixture,  and  then  put  on  a  fresh  leaf.  Six  died  on 
the  fourth,  two  on  the  fifth  and  two  on  the  seventh  day. 
The  strength  of  the  mixture  used  in  this  trial  was  in  the 
proportion  of  1  part  to  50  parts  of  water. 

"  SULPHO-NAPHTHOL.'' 

No.  1. — May  15,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  on  a  leaf  which  had  been  sprayed 
with  sulpho-naphthol.  Two  died  on  the  fourth,  one  on  the 
sixth  and  one  on  the  seventh  day. 

No.  2. — May  15,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  on  a  leaf  and  both  sprayed  with 
sulpho-naphthol.  Two  died  on  the  second,  one  on  the 
third,  one  on  the  fifth,  one  on  the  sixth  and  one  on  the 
seventh  day. 

No.  3. — May  15,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  in  a  dish  and  sprayed  with  sulpho- 
naphthol,  then  placed  on  a  fresh  leaf.  Three  died  on  the 
second  and  one  on  the  fourth  day.  The  strength  of  the 
sulpho-naphthol  used  in  this  trial  was  in  the  proportion  of 
1  part  to  100  parts  of  water. 

No.  4.— May  22,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  on  a  leaf  which  had  been  sprayed 
with  sulpho-naphthol.  Three  died  on  the  fourth,  two  on 
the  fifth,  one  on  the  sixth,  three  on  the  seventh  and  one  on 
the  ninth  day. 

No.  5.— May  22,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  on  a  leaf  and  sprayed  with  sulpho- 
naphthol.  Eight  died  on  the  fourth,  one  on  the  fifth  and 
one  on  the  sixth  day. 


INSECTICIDES.  485 

No.  6.  —May  22,  1894.  Ten  caterpillars,  before  the 
first  molt,  were  placed  in  a  dish  and  sprayed  with  sulpho- 
naphthol,  and  then  put  on  a  fresh  leaf.  Six  died  on  the 
fourth,  one  on  the  fifth,  one  on  the  sixth  and  two  on  the 
seventh  day.  The  strength  of  the  sulpho-naphthol  used  in 
this  trial  was  in  the  proportion  of  1  part  to  50  parts  of 
water. 

CYANIDES. 

Studies  on  the  anatomy  of  the  caterpillars,  made  in  1894, 
by  Mr.  Kirkland,  showed  that  the  contents  of  the  alimentary 
canal  were  strongly  alkaline.  This  suggested  the  idea  that 
some  compound  might  be  prepared  which  would  be  inert 
under  ordinary  circumstances,  but  when  taken  into  the  diges- 
tive system  of  the  insect  would  decompose  in  the  alkaline 
medium  and  form  a  deadly  poison.  Following  out  this  idea, 
Mr.  Moulton  prepared  a  number  of  the  compounds  of  cyanic 
acid,  which  were  experimented  with  during  the  summer  of 
1895.  The  substances  tried  were  the  cyanides  of  lead, 
copper,  antimony,  zinc  and  mercury.  The  last-mentioned 
compound  burned  the  foliage  badly,  hence  but  few  experi- 
ments were  made  with  it.  Of  the  other  compounds,  cyanide 
of  copper  was  the  only  one  which  gave  effective  results,  and 
these  were  not  as  satisfactory  as  can  be  obtained  from  the 
use  of  the  same  weight  of  Paris  green.  The  other  cyanides 
are  practically  valueless,  since  caterpillars  were  fed  through- 
out their  entire  life  on  foliage  treated  with  large  proportions 
of  these  three  compounds,  without  suffering  injurious  effects. 

CONTACT  INSECTICIDES. 

Whale-oil  soap,  several  proprietary  soap  powders,  soft 
soap  and  kerosene  emulsion  were  experimented  with  during 
the  summer  of  1891,  for  the  purpose  of  finding  a  cheap  con- 
tact insecticide,  for  use  where  the  caterpillars  cluster  in 
masses  on  trees,  fences,  etc.  All  of  these  insecticides  were 
found  to  be  fairly  effective. 

FOOD  SELECTION. 

The  following  experiments  were  conducted,  both  at  the 
storehouse  and  in  the  field,  by  Mr.  Kirkland,  during 


486  THE   GYPSY  MOTH. 

the  summer  of  1894,  to  determine,  if  possible,  whether  the 
gypsy  moth  caterpillars  are  able  in  any  way  to  select  their 
food,  and  thus  choose  the  non-poisoned  leaves  in  preference 
to  leaves  treated  with  arsenical  poisons.  For  this  purpose, 
a  definite  number  of  caterpillars  were  confined  upon  leaves 
treated  with  poisons  applied  in  various  ways,  and  the  results 
carefully  noted  for  several  days,  or  as  long  as  there  was  a  suf- 
ficient amount  of  food  for  them  to  eat  without  being  forced 
to  partake  of  either  the  poisoned  or  non-poisoned  leaves. 

Experiment  No.  1. — Six  elm  leaves  were  selected,  and 
a  series  of  bands  and  dots  painted  upon  each,  with  Paris 
green,  in  the  proportion  of  3  Ibs.  to  150  gal.  of  water. 
When  the  poison  was  sufficiently  dry,  so  that  it  did  not  run 
upon  the  surface  of  the  leaves,  each  one  was  placed  in  a  box 
with  three  fourth-molt  caterpillars.  Sixty-five  per  cent,  of 
the  feeding  was  upon  the  unpainted  parts  of  the  leaves  and 
thirty-five  per  cent,  upon  the  painted  parts. 

Experiment  No.  2. — A  series  of  bands  and  dots  was 
painted  upon  six  willow  leaves,  with  Paris  green,  in  the 
proportion  of  3  Ibs.  to  150  gal.  of  water.  After  the  poison 
had  been  applied,  each  leaf  was  placed  in  a  box  with  three 
caterpillars  of  the  fourth  molt.  These  fed  about  equally 
upon  the  painted  and  unpainted  parts. 

Experiment  No.  3.  —  Six  willow  leaves  were  selected, 
and  a  number  of  transverse  bands  painted  upon  each  with 
Paris  green,  in  the  proportion  of  3  Ibs.  to  150  gal.  of  water. 
The  bands  were  one-fourth  of  an  inch  wide,  and  the  un- 
painted space  between  them  one-half  of  an  inch  in  width. 
Each  leaf  was  then  placed  in  a  box  with  three  fourth-molt 
caterpillars.  Sixty  per  cent,  of  the  feeding  was  upon  the 
non-poisoned  part  of  the  leaves  and  forty  per  cent,  upon 
the  poisoned  parts. 

Experiment  No.  4.  —  A  medium-sized  twig  on  an  apple 
tree  was  selected,  and  from  it  were  removed  all  the  damaged 
and  a  part  of  the  perfect  leaves,  so  that  there  were  only 
twenty-five  leaves  left  upon  the  twig.  On  each  of  these 
were  painted  three  broad,  transverse  bands,  with  Paris 
green  and  lime  in  water,  in  the  proportion  of  3  Ibs.  of 
Paris  green  and  5  Ibs.  of  lime  to  150  gal.  of  water.  Ten 


INSECTICIDES.  487 

caterpillars  of  all  sizes  below  the  third  molt  were  then 
placed  upon  the  twig,  and  sacked  in  by  drawing  a  bag, 
made  of  cheese  cloth,  over  it,  and  tying  the  open  part 
closely  around  the  base  of  the  twig,  to  prevent  the  escape 
of  the  caterpillars.  Sixty  per  cent,  of  the  feeding  was  upon 
the  unpoisoned  and  forty  per  cent,  upon  the  poisoned  por- 
tion of  the  leaves. 

Experiment  2fb.  5.  —  Three  large  willow  leaves  were 
painted  with  Paris  green,  in  the  proportion  of  3  Ibs.  to  150 
gal.  of  water,  as  follows:  on  leaf  No.  1,  three  transverse 
bands ;  on  leaf  No.  2,  three  oblique  bands ;  on  leaf  No.  3, 
a  band  one-fourth  of  an  inch  in  width  around  the  entire 
margin  of  the  leaf.  Each  leaf  was  then  placed  in  a  box  with 
a  full-grown  caterpillar.  Leaf  No.  1  was  eaten  equally  on 
the  poisoned  and  unpoisoned  areas ;  leaf  No.  2  was  eaten 
wholly  upon  the  unpoisoned  parts  ;  leaf  No.  3  had  the  mar- 
gin eaten  in  two  places. 

Experiment  No.  6.  — Three  willow  leaves  were  prepared 
in  the  same  manner  as  in  the  preceding  experiment,  except 
that,  besides  the  Paris  green,  5  Ibs.  of  lime  were  added  to 
the  water.  Leaf  No.  1  had  a  long,  narrow  strip  eaten  from 
the  margin,  passing  through  the  ends  of  the  three  trans- 
verse bands  of  poison ;  leaf  No.  2  was  eaten  equally  on  the 
poisoned  and  unpoisoned  parts  ;  leaf  No.  3  was  eaten  deeply 
on  the  margin. 

Experiment  No.  7.  — Three  willow  leaves  were  prepared 
as  before,  using  arsenate  of  lead,  in  the  proportion  of  6  Ibs. 
to  150  gal.  of  water,  instead  of  Paris  green  and  lime.  Leaf 
No.  1  was  eaten  equally  from  the  painted  and  unpainted 
portions  ;  No.  2  was  eaten  in  the  same  manner ;  and  No.  3 
had  the  margin  eaten  in  two  places. 

Experiment  JVb.  8.  —  A  small  twig  of  oak,  bearing  six 
leaves,  was  sprayed  with  Paris  green,  in  the  proportion  of 
10  Ibs.  to  150  gal.  of  water,  and  another  twig,  bearing  the 
same  number  of  leaves,  was  left  unsprayed.  Both  were 
enclosed  in  a  sack  with  ten  full-grown  caterpillars.  July 
15.  The  greater  part  of  the  feeding  was  upon  the  unsprayed 
leaves.  July  16.  More  was  eaten  from  the  unpoisoned 
than  the  poisoned  leaves,  yet  six  of  the  caterpillars  had  died. 


488  THE   GYPSY  MOTH. 

Experiment  No.  9. — Two  twigs  of  wild  cherry  were 
trimmed  so  that  only  six  leaves  remained  on  each.  One  of 
these  twigs  was  sprayed  with  Paris  green,  in  the  proportion 
of  3  Ibs.  to  150  gal.  of  water,  and  the  other  was  left  un- 
sprayed.  Ten  full-grown  caterpillars  were  placed  upon 
the  twigs,  which  were  then  enclosed  in  a  sack.  July  15. 
None  of  the  leaves  were  eaten.  July  16.  Very  little  was 
eaten  from  the  unpoisoned  leaves  and  a  larger  amount  from 
the  poisoned  leaves.  July  17.  The  result  was  the  same. 
July  18.  Ten  times  as  much  had  been  eaten  from  the 
poisoned  as  from  the  unpoisoned  leaves.  July  19.  Nearly 
all  of  the  leaves  upon  the  poisoned  twig  had  been  eaten, 
and  but  a  small  portion  on  the  unpoisoned.  Three  of  the 
caterpillars  died. 

Experiment  No.  10. — A  twig  of  apple,  bearing  five 
leaves,  was  thoroughly  sprayed  with  Paris  green  and  lime 
in  water,  in  the  proportion  of  3  Ibs.  of  Paris  green  and  5 
Ibs.  of  lime  to  150  gal.  of  water,  and  a  similar  twig  was  left 
unsprayed.  Ten  full-grown  caterpillars  were  sacked  in 
upon  the  two  twigs.  The  first  day  the  larger  part  of  the 
feeding  was  upon  the  poisoned  leaves  ;  on  the  succeeding 
day  nearly  all  of  the  poisoned  and  about  half  of  the  un- 
poisoned leaves  were  eaten. 

Experiment  No.  11.  — Alternate  leaves  of  a  twig  of  wild 
cherry  were  painted  with  Paris  green  and  lime,  in  the  pro- 
portion of  3  Ibs.  of  Paris  green  and  5  Ibs.  of  lime  to  150  gal. 
of  water,  in  such  a  manner  as  to  cover  the  entire  surface  of 
the  leaves.  Ten  fourth-molt  caterpillars  were  then  sacked 
in  upon  the  twig.  The  feeding  was  nearly  equal  upon  the 
poisoned  and  unpoisoned  leaves. 

Experiment  No.  12. — A  twig  of  apple  was  prepared  in 
the  same  way,  using  arsenate  of  lead,  in  the  proportion  of  3 
Ibs.  to  150  gal.  of  water,  and  ten  fifth-molt  caterpillars  were 
sacked  in  upon  it.  Nearly  all  of  the  feeding  was  upon  the 
poisoned  leaves. 

Experiment  No.  13.  —  A  twig  of  wild  cherry  was  sprayed 
with  arsenate  of  lead,  in  the  proportion  of  6  Ibs.  to  150  gal. 
of  water,  and  a  similar  twig  on  the  same  branch  left 
unsprayed.  Ten  caterpillars  of  the  fifth  molt  were  sacked 


INSECTICIDES.  489 

iii  upon  the  twigs.  The  amount  eaten  upon  each  twig  was 
about  equal,  possibly  a  little  more  from  the  unpoisoned 
than  from  the  poisoned  twig. 

Experiment  JVb.  14. — A  twig  of  apple  was  sprayed  with 
arsenate  of  lead,  in  the  proportion  of  2  Ibs.  to  150  gal.  of 
water,  and  a  similar  twig  left  unsprayed.  These  twigs 
were  enclosed  in  a  sack  containing  ten  caterpillars  of  the 
fifth  molt.  The  feeding  was  about  equal  upon  the  poisoned 
and  unpoisoned  leaves. 

Experiment  No.  15. — Alternate  leaves  on  a  small  twig 
of  apple  were  painted  with  arsenate  of  lead,  in  the  propor- 
tion of  6  Ibs.  to  150  gal.  of  water,  and  ten  caterpillars  of 
the  fifth  molt  were  sacked  in  upon  it.  The  poisoned  and 
unpoisoned  leaves  were  eaten  equally. 

Summary. 

Of  the  four  experiments  where  the  caterpillars  ate  more 
of  the  poisoned  than  of  the  unpoisoned  leaves,  Nos.  9  and 
10  give  most  decided  results  against  the  choice  of  unpoi- 
soned food.  Of  the  four  cases  where  the  caterpillars  ate 
more  from  the  unpoisoned  than  from  the  poisoned  food, 
Nos.  1,  3  and  4  give  but  a  small  margin  upon  which  to  base 
a  conclusion.  The  fourth,  No.  8,  is  of  somewhat  doubtful 
value,  because  six  of  the  caterpillars  died  upon  the  second 
day  of  the  experiment.  Balancing  experiments  Nos.  1,  3, 
4  and  8  against  Nos.  6,  9,  10  and  12,  there  remain  seven 
experiments  where  there  was  no  apparent  choice  of  food. 

A  fair  conclusion  from  these  results  is  that  there  was 
no  discrimination  against  foliage  treated  with  the  poisons 
employed. 

EFFECT  OF  INSECTICIDES  ON  FOLIAGE. 

No.  1.— June  26,  1893.  A  mixture  of  f  Ib.  of  Paris 
green,  £  Ib.  of  lime  and  2  quarts  of  glucose  to  150  gal.  of 
water  was  applied  to  some  quince  bushes.  About  one- 
fourth  of  the  leaf  surface  was  destroyed  by  burning. 

No.  2. — July  12,  1893.  A  branch  of  apple  tree  was 
sprayed  with  Paris  green  and  lime,  in  the  proportion  of  1 


490  THE   GYPSY   MOTH. 

Ib.  of  each  to  150  gal.  of  water.  The  branch  was  sprayed 
twice,  on  account  of  rain.  The  foliage  was  very  badly 
burned. 

No.  3  _  july  12,  1893.  A  branch  of  apple  tree  was 
sprayed  with  the  same  mixture,  and  by  July  30  the  foliage 
was  very  badly  burned. 

No.  4. — July  12,  1893.  In  order  to  get  as  near  as 
possible  the  exact  effects  of  lime  on  the  foliage,  the  two  fol- 
lowing experiments  were  used  as  checks  on  those  preceding. 
They  were  sprayed  within  an  hour  of  each  other,  and  all 
conditions  were  as  nearly  the  same  as  it  was  possible  to 
have  them.  In  this  experiment  a  branch  of  hop-hornbeam 
was  used  as  a  check  to  No.  1.  The  branch  was  resprayed, 
on  account  of  rain.  July  30,  the  foliage  was  burned  worse 
than  that  of  experiment  No.  1,  even  though  the  branch  in 
the  latter  had  been  sprayed  three  times. 

No.  5.  — July  12,  1893.  An  apple-tree  branch  was  used 
as  a  check  to  experiment  No.  2.  The  branch  was  resprayed, 
on  account  of  rain,  and  August  6  the  foliage,  though  some- 
what burned,  was  not  as  much  so  as  in  experiment  No.  2. 

No.  6. — July  12,  1893.  An  apple-tree  branch  was 
sprayed  with  Paris  green,  in  the  proportion  of  1  Ib.  to  150 
gal.  of  water,  the  mixture  having  been  allowed  to  stand  for 
nearly  three*  hours.  August  6  the  foliage  was  very  badly 
burned. 

No.  7. — July  13,  1893.  A  branch  of  hop-hornbeam  was 
sprayed  with  Paris  green  and  lime,  in  the  proportion  of  1 
Ib.  each  to  100  gal.  of  water.  The  branch  was  resprayed 
twice,  on  account  of  rain.  July  27,  the  foliage  was  very 
badly  burned. 

No.  8. — July  12,  1893.  A  branch  of  apple  tree  was 
sprayed  with  arsenic,  in  the  proportion  of  1  Ib.  to  25  gal. 
of  water.  July  19,  the  branch  was  resprayed,  on  account 
of  rain,  and  again  on  the  25th.  August  6,  the  foliage  was 
badly  burned. 

No.  9. — July  20,  1893.  A  branch  of  apple  tree  was 
sprayed  with  arsenate  of  zinc,  in  the  proportion  of  1  Ib.  to 
50  gal.  of  water.  August  6,  the  foliage  was  badly  burned. 

No.  10. — July  1,  1893.     A  small  hop-hornbeam  branch 


INSECTICIDES.  491 

was  immersed  in  a  solution  of  2  Ibs.  of  arsenate  of  lead 
mixture,  making  1  Ib.  of  precipitate  to  150  gal.  of  water. 
Foliage  uninjured. 

No.  11. — July  1,  1893.  This  experiment  was  similar  to 
the  one  preceding,  except  that  the  branch  was  sprayed,  in- 
stead of  being  immersed.  A  branch  of  a  small  oak  tree  was 
sprayed  with  arsenate  of  lead  mixture,  in  the  proportion  of 
2  Ibs.  to  150  gal.  of  water.  Foliage  uninjured. 

The  "burning"  effect  of  Paris  green,  when  used  in  any 
proportion  greater  than  1  Ib.  to  150  gal.  of  water,  has  been 
ascribed  to  the  presence  of  a  small  quantity  of  soluble 
arsenic  contained  in  the  poison.  Many  chemists  and  ento- 
mologists have  recommended  the  addition  of  lime  to  the 
mixture  of  Paris  green  and  water  used  in  spraying,  in  order 
to  neutralize  this  soluble  arsenic.  Our  experiments,  how- 
ever, have  tended  to  prove  that  the  addition  of  lime  is  of 
questionable  value. 

In  some  cases  we  have  used  a  considerable  strength  of 
Paris  green  and  lime  without  burning  the  foliage,  while  in 
other  cases  a  marked  burning  has  resulted.  The  same  vari- 
ation in  burning  effects  is  often  noticed  where  Paris  green 
is  used  alone.  We  are  led  to  believe  that  the  burning 
caused  by  the  use  of  Paris  green  and  lime  is  dependent  in  a 
great  measure  upon  the  amount  of  lime  added,  and  also 
upon  the  length  of  time  the  mixture  is  allowed  to  stand, 
as  our  experiments  have  shown  that,  where  a  consider- 
able quantity  of  lime  is  added  to  the  Paris  green  mixture 
and  allowed  to  stand  for  some  time,  there  is  far  greater 
danger  of  burning  the  foliage  than  there  would  be  from  the 
use  of  Paris  green  alone,  thus  apparently  indicating  that 
the  lime  decomposes  the  Paris  green  in  part,  and  forms  a 
more  soluble  compound  of  arsenic. 

At  my  request,  Dr.  Charles  Wellington,  professor  of 
chemistry  at  the  Massachusetts  Agricultural  College,  has 
made  a  series  of  analyses  of  Paris  green  mixed  with  water 
and  of  Paris  green  and  lime  mixed  with  water,  with  a  view 
of  determining  whether  the  lime  would  decompose  the 
arsenite  of  copper  contained  in  the  Paris  green,  and  in- 
crease the  per  cent,  of  soluble  arsenic  in  the  mixture.  An 


492 


THE   GYPSY   MOTH. 


extract  from  his  report  on  the  result  of  these  investigations 
is  given  below  :  — 

Paris  green,  a  preparation  of  arsenite  of  copper,  is  insoluble  in 
water,  but  yields  to  it  a  small  amount  of  arsenious  oxide,  with  a 
mere  trace  of  copper. 

The  Paris  green  employed  in  these  examinations  was  a  mixture 
of  several  samples,  all  obtained  from  the  Hampden  Paint  and 
Chemical  Company  of  Springfield,  Mass. 

Its  composition  was  as  follows  :  — 


Water, 

Copper  oxide, 
Arsenious  oxide,     . 
Insoluble,        .... 
Other  material  and  difference, 


Total, 


Per  Cent. 

1.20 
30.46 

59.94 

.12 

8.28 

100.00 


After  allowing  mixtures  of  Paris  green  and  water  to  stand  with 
occasional  agitation,  I  have  found  the  following  amounts  of  arse- 
nious oxide  in  solution :  — 


TAKEN*. 

Time 

Found  Arsenious 

Paris  Green 
(Pounds). 

Lime  (Pounds). 

Water 
(Gallons). 

of  Standing 
(Hours). 

Oxide  (Grains 
per  Gallon). 

«,           .           .          1 

None. 

150 

3 

0.33 

6,        .        .        1 

None. 

100 

3 

0.46 

c,         .        .        1 

None. 

125 

i 

0.11 

The  free  arsenious  acid  would  appear  to  be  the  cause  of  the 
damage  to  the  foliage. 

Alkaline  substances  generally  neutralize  arsenious  acid,  forming 
with  it  salts  known  as  arsenites.  Lime,  soda  and  potash  are 
materials  which  thus  act.  Any  one  of  these  could  be  added  to 
the  mixture  in  such  proportion  as  to  exactly  neutralize  all  free 
acid. 

These  substances,  however,  are  sufficiently  powerful  as  bases  to 
withdraw  the  arsenious  acid  from  the  copper.  This  is  accom- 
plished either  partially  or  wholly,  according  to  the  favoring  cir- 


ANALYSES  OF  PARIS  GREEN. 


493 


cumstances  of  concentration  and  heat.  In  moderately  concentrated 
solutions  of  soda  or  potash  (i.e.,  sodium  hydrate  or  potassium 
hydrate)  all  the  copper  is  removed  from  Paris  green  as  insoluble 
cuprous  oxide.  Soluble  soda  or  potassa  arsenite  is  then  formed. 

In  such  dilute  solutions  as  are  here  considered,  this  could  not 
occur,  and  yet  considerable  portions  of  the  arsenious  acid  may  be 
removed  from  the  copper  compound.  To  show  this,  I  have  made 
the  following  determinations  with  the  use  of  lime.  In  each  case  the 
Paris  green  and  lime  were  mixed,  placed  in  the  water,  the  mixture 
agitated  occasionally  and  at  the  end  of  the  designated  time  fil- 
tered :  — 


TAKEN. 

Time 

Found  Arsenious 

Paris  Green 
(Pounds). 

Lime  (Pounds). 

Water 

(Gallons). 

of  Standing 
(Hours). 

Oxide  (Grains 
Per  Gallon). 

d,      .       .       1 

5 

50 

3 

0.77 

e,        .        .        1 

5 

100 

3 

0.92 

/,        .        .        1 

5 

125 

3 

1.09 

9*       •        •        1 

5 

150 

3 

1.33 

By  substituting  for  this  very  large  amount  of  lime  smaller  quan- 
tities, proportionally  smaller  quantities  of  arsenious  oxide  were 
dissolved. 

To  illustrate  the  relative  solvent  effect  in  different  periods  of 
time,  the  following  determinations  serve  :  — 


TAKEN. 

Time 

Found  Arsenious 

Paris  Green 
(Pounds). 

Lime  (Pounds). 

Water 
(Gallons). 

of  Standing 
(Hours). 

Oxide  (Grains 
Per  Gallon). 

h,          .            .            1 

5 

125 

j 

0.69 

t,           .            .            1 

5 

150 

I 

0.74 

y,     .     .     i 

5 

125 

3 

1.09 

\    .     .     i 

5 

125 

10 

1.23 

Trials  with  the  use  of  soda  gave  the  following  results :  — 


TAKEN. 

Time 
of  Standing 
(Hours). 

Found  Arsenious 
Oxide  (Grains 
Per  Gallon). 

Paris  Green 

(Pounds). 

Soda  (Pounds). 

Water 

(Gallons). 

J,           .           .           1 

m,      .        .        I 

I 

125 
125 

1 

0.17 

0.31 

494 


THE   GYPSY  MOTH. 


The  lime  is  understood  to  be  quicklime,  the  soda  to  be  crystal- 
lized neutral  soda  carbonate. 

It  is  thus  seen  that  either  with  the  use  of  lime  or  of  soda  a 
certain  quantity  of  arsenious  oxide  is  removed  from  Paris  green 
beyond  that  which  water  alone  would  remove.  The  actual  amount 
removed  depends  upon  the  proportions  of  the  substances  mixed, 
as  well  as  the  time  allowed  for  solution.  In  every  case  this  amount 
is  in  the  form  either  of  lime  or  soda  arsenite,  and  is  in  solution. 

The  "  burning"  of  foliage  which  occurs  as  the  result  of 
spraying  with  arsenical  poisons  is  due  to  the  presence  of 
soluble  arsenic,  which  is  found  to  some  extent  in  Paris 
green  and  to  a  greater  degree  in  London  purple.  Other 
poisons  which  contain  arsenic  in  a  practically  insoluble 
form,  as,  for  instance,  arsenate  of  zinc,  when  sprayed  on 
the  foliage  and  fully  exposed  to  atmospheric  influences  as 
well  as  to  the  physiological  action  exerted  by  the  leaves 
themselves,  sometimes  decompose  to  a  certain  extent,  and 
give  rise  to  soluble  compounds  of  arsenic.  The  effect  of 
soluble  arsenic  on  leaves  is  to  kill  the  protoplasmic  contents 
of  the  cells  which  compose  the  living  or  assimilative  part 
of  the  leaf,  as  is  shown  by  the  illustrations  given  below  :  — 


FIG.  1.  Section  through  normal  leaf  of 
pig-nut  hickory  (Carya porcina) ,  show- 
ing structural  elements.  E,  epidermis ; 
PC,  palisade  cells;  SP,  spongy  paren- 
chyma; S,  stoma  or  breathing  pore. 
(After  Kirkland.) 


FIG.  2.  Section  through  leaf  of  same 
tree,  "burned"  by  excess  of  Paris 
green.  Cell  contents  (protoplasm)  of 
palisade  cells  and  spongy  parenchyma 
dead  and  dried  up ;  cell  walls  shrivelled. 
(After  Kirkland.) 


LEAF  AREA  or  TREES. 

To  gain  a  better  knowledge  of  the  surface  which  needs  to 
be  covered  in  spraying  operations,  during  the  summer  of 


LEAF  AREA  OF  TREES.  495 

1895  studies  were  made,  under  my  direction,  by  Messrs. 
Kirkland  and  Hylan,  upon  the  leaf  area  of  three  average- 
sized  trees,  as  follows  :  — 

The  dimensions  of  a  medium-sized  Baldwin  apple  tree 
were  carefully  measured  and  the  leaves  upon  one-fourth  of 
the  tree  counted.  The  average  area  of  a  single  leaf  was 
computed  by  careful  measurement  of  ten  average  leaves, 
and  the  total  leaf  area  ascertained  by  multiplying  the  whole 
number  of  leaves  by  this  last  factor.  The  data  concerning 
the  tree  are  given  below :  — 

Height  of  tree,  23  feet. 
Diameter  of  top,  23  feet,  9  inches. 
Diameter  of  trunk,  1  foot,  5£  inches. 
Number  of  leaves,  99,040. 

Average  area  of  single  leaf,  30.188  square  centimeters. 
Leaf  area  of  tree,  298.981952  square  meters  or  3,218.25  square 
feet. 

A  second  Baldwin  apple  tree  afforded  data  as  follows  :  — 

Height,  18  feet,  5  inches. 
Diameter  of  top,  26  feet,  7  inches. 
Diameter  of  trunk,  1  foot,  5£  inches. 
Number  of  leaves,  108,540. 

Average  area  of  single  leaf,  29.294  square  centimeters. 
Leaf  area  of  tree,  317.957076  square  meters  or  3,422.49  square 
feet. 

The  leaf  area  of  a  red  oak  (  Quercus  rubra)  was  computed 
with  the  following  result :  — 

Height  of  tree,  41  feet,  6  inches. 

Diameter  of  top,  37  feet. 

Diameter  of  trunk,  1  foot,  3  inches. 

Number  of  leaves,  35,764. 

Average  area  of  single  leaf,  83.5705  square  centimeters. 

Leaf  area  of  tree,  298.88  square  meters  or  3,217.16  square  feet. 

In  the  actual  spraying  of  trees  the  poison  mixture  should 
be  thoroughly  applied  to  both  surfaces  of  the  leaf;  so  that, 
to  find  the  amount  of  surface  necessary  to  be  covered  in 
spraying  these  trees,  the  area  should  be  doubled. 


APPENDICES. 


APPENDIX   A. 


REPOKT  OF    A  CONFERENCE    HELD  AT  THE  ROOMS   OF    THE 
STATE  BOARD    OF  AGRICULTURE,  BOSTON,  MASS. 

MAKCH  4,  1891. 

Present :  Profs.  C.  V.  RILEY  and  C.  H.  FERNALD,  Mr.  SAMUEL 
SCUDDEE  of  Cambridge,  Mayor  WIGGIN  of  Maiden,  Selectmen 
L.  S.  GOULD  of  Melrose,  W.  C.  CRAIG  of  Medford,  and  W.  A. 
PIERCE  of  Arlington,  Messrs.  SHALER,  APPLETON  and  SESSIONS  of 
the  Gypsy  Moth  Commission,  and  others. 

Professor  SHALER.  You  know  that  about  twenty  years  ago  an 
interesting  Frenchman  brought  an  interesting  bug  to  this  country. 
His  name  was  Trouvelot,  and  he  brought  the  creature  thinking  to 
introduce  it  as  a  valuable  silk-worm.  I  begged  him  to  destroy 
his  specimens,  and  at  one  time  he  said  he  had.  It  appears,  how- 
ever, that  they  got  away  from  him.  Last  year  I  went  before  the 
Legislature  and  begged  for  some  money,  advising  them  to  put  a  hun- 
dred thousand  dollars  at  the  disposition  of  a  trustworthy  commission. 
They  appropriated  fifty  thousand  dollars  and  appointed  a  commission 
which  did  a  good  deal  of  work  and  expended  a  good  deal  of  money 
and  energy.  I  begged  them  to  bend  their  energies  to  bringing  in  the 
boundaries  as  far  as  possible,  to  pay  the  market  price  for  eggs  and 
grubs,  and  to  put  their  inspection  work  in  progress  ;  but  they  went 
into  a  miscellaneous  sprinkling  and  burning  over  the  whole  terri- 
tory. The  result  now  is  that,  as  nearly  as  I  can  ascertain,  it 
would  take  a  line  thirty  miles  long  to  enclose  the  area  these  insects 
occupy.  They  are  found  in  a  territory  of  not  far  from  fifty  square 
miles,  though  not  all  over  it.  I  should  think  that  not  more  than 
ten  square  miles  were  solidly  occupied.  On  the  rest  of  it  there 
are  colonies  here  and  there.  The  situation  seems  to  me  discour- 
aging in  a  certain  way,  but  it  is  an  encouraging  fact  that  in  about 
twenty  years  they  have  not  occupied  more  than  about  fifty  square 
miles,  and  it  shows  that  they  are  not  to  be  readily  transported  to  a 
great  distance.  Another  encouraging  fact  is  that,  as  far  as  I  can 
learn,  save  at  two  or  three  very  limited  points  south  of  the  Charles 
River,  the  creature  may  be  enclosed  in  this  line  on  this  side  the 


iv  THE   GYPSY  MOTH. 

river  [a  map  was  shown] ,  which  it  does  not  seem  to  have  passed 
easily.  It  passed  these  few  points  probably  in  hauling  manure. 

Professor  FERNALD.  Are  you  quite  sure  of  the  boundaries? 
They  are  reported  in  Maine  and  Western  Massachusetts. 

Professor  SHALEK.  I  know  they  are,  but  putting  the  worst  face 
upon  it,  as  I  am  at  present  doing,  I  think  an  area  of  something 
like  five  by  ten  miles  is  the  region  that  has  got  to  be  closely 
studied.  There  is  a  reasonable  suspicion  of  it  over  an  area  of  say 
fifty  square  miles,  and  the  work  has  got  to  be  done  over  that  area. 
One  of  the  discouraging  features  is  that  there  is  a  great  traffic 
through  this  territory.  Railroads  and  wagon  roads  go  through  it, 
and  there  is  a  large  traffic  in  manure  out  of  the  district.  "We  have 
twenty-four  thousand  dollars  to  spend  for  certain,  and  I  am  sure 
the  Legislature  will  give  us  anything  in  reason  we  ask  for. 

Mr.  APPLETON.  It  seems  to  me  the  situation  is  this :  Can  we 
eradicate  this  thing,  and,  if  so,  how?  If  we  cannot  eradicate  it 
entirely,  what  is  the  best  we  can  do  ?  Now,  the  first  question  to 
consider,  it  seems  to  me,  is,  Can  we  eradicate  it,  or  not? 

Professor  SHALER.  We  should  like  to  have  the  opinion  of  ex- 
perts on  that  point.  Professor  Riley,  will  you  give  us  your  word  ? 

Professor  RILEY.  I  will  be  very  glad  to  give  you  whatever 
suggestions  I  can  on  the  subject.  I  have  taken  the  same  interest 
in  this  matter  since  it  was  so  prominently  announced  that  I  do  in 
all  matters  of  applied  entomology,  and  I  have  felt  that  in  the  main 
Professor  Fernald's  original  suggestions  were  very  wise.  The  in- 
sect, as  Professor  Shaler  has  well  said,  has  but  limited  powers  of 
spreading.  While  the  female  has  wings,  it  is  heavy  bodied  and 
flies  but  little,  and  the  history  of  the  past  twenty  years  shows  that 
its  spread  has  been  very  gradual.  Therefore  we  have  a  condition 
of  affairs  totally  different  from  that  prevailing  in  the  insect's  native 
home,  Europe,  and  we  are  justified  in  making  a  strong  effort  to 
undo  the  harm  that  has  been  done.  That  brings  up,  first  of  all, 
the  question :  Is  it  practicable  to  exterminate  it,  or  not  ?  In  view 
of  Professor  Shaler's  statement,  I  have  serious  doubts,  because,  if 
it  may  be  said  to  occur  in  an  area  of  say  fifty  square  miles,  if  it  is 
found  even  in  a  number  of  central  points  of  distribution  in  that 
area,  there  is  great  danger,  in  my  judgment.  My  own  fears  would 
be  that  it  has  got  into  the  woods  and  on  to  trees  that  are  not  so 
easily  treated.  So  long  as  it  was  confined  to  cultivated  trees  and 
plants  under  cultivation  I  think  there  would  have  been  no  difficulty 
at  all,  and  the  authorities  would  have  been  blameworthy  in  allow- 
ing it  to  go  out  from  Massachusetts  over  the  rest  of  the  country. 

Professor  SHALER.  I  don't  think  it  has  gotten  into  the  woods. 
I  think  it  is  still  confined  to  the  artificial  grounds,  as  yet. 


APPENDIX.  v 

Mr.  APPLETON.  Don't  you  think  it  would  be  a  good  plan  to 
ask  these  gentlemen  representing  the  different  towns  what  their 
experience  is  in  that  direction  ? 

Mr.  CRAIG  thought,  in  a  general  way,  that  they  did  not  attack 
forest  trees ;  were  confined,  as  a  rule,  to  orchard  trees  and  trees 
surrounding  houses.  Thought  the  reason  the  spread  was  not 
greater  the  last  twenty  years  was  because  the  people  took  the  in- 
sect for  some  kind  of  canker-worm,  and  took  pains  to  burn  them 
off  the  trees,  which  they  did  until  they  became  too  numerous  to 
control.  He  recommended  the  use  of  tarred  paper  tied  round  the 
trees  with  a  string.  Undoubtedly  the  commissioners  had  destroyed 
a  great  many  of  the  insects. 

Professor  RILEY.  It  is  well  known  to  feed  upon  a  number  of 
different  forest  trees  that  grow  with  us,  and  in  the  event  of  its 
getting  beyond  cultivated  plants  I  should,  as  I  said,  have  very 
little  hope  of  its  ultimate  extermination.  I  am  not  an  alarmist, 
and  I  do  not  believe  that  our  people  need  be  so  very  seriously 
affected  if  it  is  not  exterminated ;  but,  aside  from  that,  the  loss 
would  go  on  increasing  annually,  and  it  would  become  a  very 
grievous  additional  pest  to  those  the  farmer  and  fruit  grower 
already  have  to  contend  with.  The  thing  you  have  to  consider  is- 
this :  from  what  I  could  gather  from  the  accounts  in  the  news- 
papers, three  measures  were  adopted:  first,  by  attempting  to 
destroy  the  eggs ;  secondly,  by  attempting  to  destroy  the  cater- 
pillars after  they  had  hatched  by  means  of  arsenical  spraying ; 
thirdly,  by  endeavoring  to  stop  the  artificial  spread  of  the  pest  on 
vehicles,  manure  wagons,  etc. 

Individually  I  have  always  felt,  and  so  expressed  myself,  and 
still  feel,  that  the  proper  way  would  be  to  use  whatever  funds  the 
State  will  give  you  during  a  limited  time,  and  concentrate  all  effort 
and  all  expenditure  in  the  month  of  June  on  the  destruction  of 
caterpillars,  and  not  to  bother  about  the  destruction  of  the  eggs  or 
the  prevention  of  the  spread  of  the  insect.  These  latter  methods, 
necessarily  intrusted  to  persons  who  may  be  efficient  or  who  may 
not,  are  apt  to  bring  the  whole  subject  into  popular  disrepute  and 
disfavor.  You  may  reduce  the  numbers,  but  you  will  never  exter- 
minate it  by  destroying  the  eggs.  Therefore,  as  a  single  spraying 
of  a  tree  will  kill  five  thousand  caterpillars  just  as  well  as  one, 
there  is  nothing  to  be  gained  by  the  work  of  destroying  the  eggs. 
Moreover,  I  do  not  believe  there  is  much  to  be  gained  in  the  work 
of  preventing  its  spread  by  the  examination  of  vehicles  on  the 
main  thoroughfares  and  on  the  railroads.  On  the  contrary,  I 
believe  that  the  only  way  to  accomplish  that  end  is  by  a  very  strict 
law  which  the  Legislature  should  pass,  giving  the  power  to  some 


vi  THE  GYPSY  MOTH. 

committee  to  absolutely  prohibit  the  sending  of  nursery  stock  or 
any  plant  growth  or  material,  probably  including  manure,  out  of 
an  infected  district  without  inspection.  My  belief  is  that  a  rigid 
quarantine  law,  making  it  a  penal  offence  for  a  nurseryman  to 
send  cuttings  or  trees  from  any  given  infected  area,  without  first 
having  the  sanction  of  this  commission,  would  be  effective  in  pre- 
venting the  spread.  That  is  to  say,  there  should  be  a  competent 
person  or  persons  appointed,  to  whom  all  such  shipments  should 
be  submitted,  and  only  upon  their  approval  should  such  shipments 
be  allowed  to  pass  out  from  that  area.  That  would  be  the  only 
simple  and  efficient  way  of  preventing  its  spread.  My  impression 
is  that  the  danger  is  far  greater  from  overlooking  a  batch  of  eggs 
during  the  months  of  the  year  when  such  a  thing  is  possible,  and 
of  the  insects  being  transmitted  in  that  way,  than  there  would  be 
in  the  mere  carrying  of  the  caterpillars.  I  would  therefore  con- 
centrate all  effort  on  the  destruction  of  the  caterpillars. 

I  believe  that  even  in  an  area  as  extended  as  Professor  Shaler 
indicates,  if  the  Legislature  would  appropriate  a  hundred  thousand 
dollars  the  thing  could  be  done.  Let  it  be  used  under  the  intelli- 
gent guidance  of  some  one  who  has  had  experience,  who  knows 
practically  how  to  spray,  who  can  go  to  work  intelligently  and 
instruct  his  men,  and  have  a  sufficient  force  to  examine  every  tree 
and  cultivated  plant  upon  which  this  insect  is  known  to  feed,  and 
make  sure  that  wherever  it  is  it  will  be  destroyed  before  the  change 
into  the  chrysalis  state  takes  place.  In  other  words,  I  do  not  see 
why,  with  one  hundred  thousand  dollars,  a  single  year  ought  not 
to  suffice  to  stamp  it  out  from  the  area  in  which  you  know  it  to  be 
found.  I  believe  it  can  be  done,  and  that  the  State  of  Massachu- 
setts would  be  justified  in  making  the  attempt. 

In  Europe  this  injury  is  at  times  not  great,  at  other  times  it  is 
quite  extensive ;  but  it  is  chiefly  notable  in  those  places  where 
there  are  very  large  areas  of  cultivated  forests.  Bavaria,  for 
instance,  has  lately  suffered  greatly  from  it.  Experience  there 
has  shown  that  it  is  easily  checked  by  the  use  of  sticky  bands, 
very  much  the  same  methods  as  you  have  employed  here  for  the 
canker-worm.  They  use  several  kinds  of  glue  (manufactured  and 
some  of  them  patented  by  different  firms),  which  is  procured  in 
large  quantities  and  smeared  on  the  trees,  being  made  in  such  a 
way  that  it  does  not  dry.  I  presume  it  comes  nearest  to  our 
printers'  roller  glue.  The  caterpillars  never  pass  above  it  from 
below.  Coming  down  the  tree  they  jump  over  it.  The  devices 
for  putting  it  on  are  very  simple.  That  is  the  method  which  ex- 
perience has  shown  to  be  the  most  satisfactory  there,  but  it  is  a 
preventive  method,  and  chiefly  to  be  considered  when  you  have 


APPENDIX.  vii 

given  up  the  fight  for  extermination.  The  main  thing  for  you  to 
do  is  to  try  to  stamp  it  out  during  the  active  season  and  use  all 
your  energies  to  that  end.  The  arsenicals  are  not  expensive,  and 
if  an  analysis  is  made  of  the  Paris  green,  or  whatever  form  of 
arsenic  is  used,  to  insure  its'  purity,  I  can  see  no  reason  why  the 
whole  area  should  not  be  practically  cleared  off  during  a  single 
season.  That  should  be  carefully  followed  up  by  close  observa- 
tion, with  a  view  of  repeating  it  in  the  case  of  some  omitted  centre 
or  point  where  they  may  be  found  in  a  subsequent  year.  In  case 
they  have  not  gone  into  the  woods,  it  seems  to  me  feasible  to  ex- 
terminate them. 

I  would  make  one  other  suggestion,  and  that  is,  that  as  an 
auxiliary  method  it  would  be  well  to  spend  five  hundred  or  six 
hundred  dollars  in  sending  one  or  two  persons  abroad  next  sum- 
mer with  no  other  object  than  to  go  to  some  section  of  northern 
Europe  to  collect  and  transmit  to  authorized  persons  here  a  certain 
number  of  the  primary  parasites  of  this  species,  which  are  known 
to  check  its  ravages  over  there.  The  insect  was  undoubtedly 
brought  over  by  Trouvelot  without  any  of  its  natural  checks.  In 
my  judgment  it  would  be  well  worth  trying  to  import  its  parasites 
from  abroad.  The  advantage  would  be  this :  if  you  failed  to 
exterminate  it  by  spraying,  its  parasites,  seeking  for  this  partic- 
ular host,  would  be  more  apt  to  find  the  overlooked  or  escaped 
specimens  than  man  would. 

Professor  FERNALD.  Do  you  think  that  any  of  our  native  par- 
asites will  be  liable  to  attack  this  insect? 

Professor  RILEY.  Experience  justifies  the  belief  that  some  of 
them  may,  in  time. 

Professor  FERNALD.     Have  we  a  case  on  record? 

Professor  RILEY.  Yes,  though  they  are  not  numerous.  Pieris 
rapce,  or  the  imported  cabbage-worm,  has  some  native  parasites. 
There  are  other  cases,  but  I  should  have  to  consult  my  notes. 

[Note  by  Professor  RILEY.  Several  native  species  attack  Scoly- 
tus  rugulosus :  the  same  is  true  of  the  hop  aphid,  Phorodon  humuli, 
and  of  several  important  species  of  bark  lice.] 

Professor  FERNALD.  In  reply  to  the  question  which  was  first 
asked,  as  to  whether  it  is  possible  to  eradicate  the  insect  at  all, 
let  me  suppose  a  case.  Suppose  we  have  a  tree  like  the  elm  I  see 
yonder,  and  suppose  we  know  it  to  be  the  only  tree  in  America 
that  is  infested.  I  think  you  will  all  agree  with  me  that  for  a  small 
sum  of  money  all  moths  on  it  could  be  destroyed.  Suppose  there 
were  two,  —  suppose  all  the  trees  on  the  Common  were  infested. 
If  they  could  be  destroyed  on  all  those  trees,  it  is  only  a  ques- 
tion of  time  and  money  to  eradicate  them  from  a  much  larger 


viii  THE  GYPSY  MOTH. 

territory.  It  is  a  question  of  time  and  intelligent  labor.  I  say 
intelligent  advisedly.  Right  here  I  would  suggest  very  earnestly 
that  the  committee  or  commission  employ  a  scientific  man  upon  it. 
This  is  the  advice  I  gave,  with  all  the  force  I  could,  to  the  former 
commission,  for  there  are  a  thousand  and  one  things  constantly 
coming  up  in  work  of  this  kind,  and  it  is  necessary  to  have  some 
one  who  knows  and  is  able  to  answer  questions.  As  to  the  ques- 
tion of  territory,  I  only  raised  that  to  know  how  it  had  been 
determined.  It  is  possible  it  is  not  so  extensive  as  indicated,  but 
it  may  be. 

Professor  SHALEK.  I  thought  it  best  to  put  it  at  the  highest 
figure.  My  own  opinion  is  that  we  shall  not  have  to  deal  with  an 
actual  area  of  more  than  nine  or  ten  square  miles. 

Professor  RILEY.  Is  it  not  true  that  so  far  you  have  found  this 
pest  chiefly  on  orchard  trees  ? 

Professor  SHALER.     On  orchard  trees  and  elms. 

Professor  RILEY.  That  is  unfortunate,  because  it  increases  the 
difficulty  of  treatment. 

Mr.  CRAIG.  They  are  more  numerous  on  and  generally  select 
orchard  trees,  but  even  pine  trees  have  been  attacked  by  them 
and  in  some  cases  the  branches  stripped.  Maple  trees  are  also 
attacked. 

Professor  SHALER.  I  have  seen  them  on  some  maple  trees  and 
heard  of  others,  but  it  seems  to  be  a  case  of  starvation  when  they 
come  to  that. 

Mr.  CRAIG.  My  observation  is  that  the  older  the  tree  the  more 
they  will  attack  it. 

Professor  FERNALD.  With  regard  to  a  scientific  man  on  the 
commission,  if  you  can  get  an  entomologist  who  is  also  a  business 
man  you  will  be  fortunate,  but  in  my  judgment  it  is  important  to 
have  a  business  man  too. 

To  go  back  to  the  question  of  territory,  I  agree  with  Professor 
Riley  that  it  is  rather  stupendous  ;  but  if  you  can  destroy  the 
insects  over  a  small  area,  why  cannot  you  over  a  large  one?  The 
whole  thing  is  experimental ;  it  is  unprecedented  to  destroy  so 
many  insects  scattered  over  so  large  a  territory,  but  my  impres- 
sion is  that  they  can  be  destroyed.  The  question  is,  how  to  do  it. 
I  was  informed  last  summer  that  Paris  green  destroyed  the  larvae 
of  this  insect  up  to  a  certain  size ;  beyond  that  size  they  were  able 
to  eat  it  and  grow  fat.  I  urged  the  commission  to  try  a  branch 
with  caterpillars  that  had  not  eaten  any  Paris  green,  but  I  cannot 
learn  that  they  did  it.  If  their  statements  are  correct,  I  must  lose 
the  little  faith  I  had  in  regard  to  the  efficacy  of  Paris  green.  My 
experiments  at  Amherst  on  the  use  of  Paris  green  do  not  seem  to 


APPENDIX.  ix 

tally  with  the  results  they  obtained.  They  used  one  pound  of 
Paris  green  to  one  hundred  and  fifty  gallons  of  water,  and  when 
Mr.  Sessions  and  I  went  over  there  in  the  summer  we  saw  that  the 
trees  were  burned  very  little.  The  same  proportions  used  at 
Amherst  burned  the  trees  very  badly.  Yet  Professor  Cook  and 
others  have  reported  that  a  much  larger  proportion  of  Paris  green 
could  be  used.  The  Paris  green  I  used  I  had  analyzed  and  know 
just  what  it  was.  I  expect  there  is  either  some  great  difference 
between  the  climate  of  Amherst  and  this  region  —  or  something 
else. 

Mr.  CRAIG.  So  far  as  my  own  orchard  is  concerned,  where  the 
Paris  green  was  used  a  streak  was  burned  here  and  there,  in  other 
places  not.  I  think  it  was  not  kept  stirred  up. 

Professor  FERNALD.  Suppose  it  is  not  possible  to  destroy  these 
insects :  even  then  I  believe  it  would  pay  to  make  annual  appro- 
priations to  hold  them  in  check.  "We  know  what  the  farmers  are 
paying  annually  to  destroy  the  potato  beetle,  and  if  this  insect 
spreads  over  the  Commonwealth  of  Massachusetts  I  should  sup- 
pose it  was  capable  of  doing  more  damage  than  the  potato  beetle. 
It  seems  to  me,  if  it  is  not  possible  to  stamp  it  out,  it  is  wise  to 
hold  it  in  check  where  it  is. 

Mr.  SESSIONS.  I  have  heard  the  idea  advanced  by  somebody 
from  Medford  that  possibly  the  reason  the  caterpillars  apparently 
eat  Paris  green  and  live  is  that  after  a  certain  stage  of  their 
existence  they  stop  eating  altogether. 

Professor  FERNALD.  They  do  not  stop  eating  long  before  they 
spin  their  cocoons.  The  time  is  not  more  than  twenty-four  hours. 

Professor  SHALER.  I  should  like  to  ask  about  the  chances  for 
more  satisfactory  insecticides.  I  should  like  to  ask  if  we  may 
reckon  among'  the  insecticides  certain  compound  salts  of  calcium 
which  are  very  acrid,  and  whether  a  solution  of  them  would  be 
efficacious  ? 

Professor  FERNALD.     I  have  had  no  experience  with  them. 

Professor  SHALER.  The  question  is,  whether  it  would  serve  in 
this  case.  Do  you  know,  Professor  Riley  ? 

Professor  EILEY.  I  should  have  most  faith  in  the  arsenicals. 
The  relative  value  of  the  different  forms  of  arsenic  spraying  depends 
partly  upon  the  kind  of  tree  treated,  partly  upon  the  condition 
of  the  atmosphere,  and  very  materially  upon  the  purity  of  the  ma- 
terial. Paris  green  has  this  advantage,  that  it  may  be  used  much 
more  strongly  with  less  injury  to  the  trees ;  and  it  has  this  disad- 
vantage, as  compared  with  London  purple  or  pure  arsenic,  that  it 
is  not  soluble  in  water,  and  you  have  to  keep  stirring  it.  I  have 
no  doubt  that  the  experience  Professor  Fernald  referred  to  was 


x  THE  GYPSY  MOTH. 

due  to  the  inferior  character  of  the  Paris  green  in  the  one  case 
and  its  purity  in  the  other.  It  should  be  applied  with  a  spraying 
nozzle  that  would  simply  touch  it  to  the  leaves,  and  it  should  be 
mixed  with  a  substance  to  make  it  adhere.  In  other  words,  all 
this  work  should  be  superintended  by  a  careful,  practical  man, 
who  knows  what  to  do.  A  part  of  the  advantage  of  using  the 
arsenicals  in  this  part  of  the  country  would  be  that,  aside  from  the 
destruction  of  Ocneria,  it  would  pay  to  use  it  as  against  the  tent 
caterpillar,  the  codling  moth  and  various  other  insects  that  are  so 
prevalent  in  your  orchards.  It  is  one  of  the  curious  things  which 
strike  a  man  travelling  through  Massachusetts  that  in  a  State 
where  applied  entomology  has  had  its  origin  in  America,  an  insect 
as  common  as  the  tent  caterpillar,  and  which  may  be  so  easily  mis- 
taken for  this  very  Ocnen'a,  should  be  so  abundant,  and  that  so 
little  should  be  done  to  control  it.  You  will  have  the  same 
trouble  with  the  Ocnen'a.  You  can't  get  the  average  Massachu- 
setts farmer  to  bestir  himself  about  it. 

Professor  SHALER.  Am  I  not  right  in  supposing  that  our  first 
care  should  be  to  drive  this  pest  in  on  the  periphery  at  all  costs, 
but  to  make  surest  of  its  destruction  on  the  periphery?  The  num- 
ber of  inspectors  we  could  have  would  be  limited,  therefore  we 
should  take  the  extremest  care  with  the  periphery.  With  that  in 
view,  how  would  it  do,  from  now  until  the  time  the  eggs  hatch 
(they  are  conspicuous  things,  —  you  can  see  them  a  great  distance, 
and  boys  could  gather  them  in  quantities) ,  to  pay  the  school-boys 
what  would  be  a  tempting  price  per  ounce  for  the  eggs?  We 
would  secure  a  very  large  destruction  on  that  basis,  I  think,  be- 
tween now  and  the  time  the  eggs  hatch.  We  could  put  a  person 
in  each  town  who  should  gather  the  eggs  once  a  day,  pay  for  and 
destroy  them,  —  that  is.  in  the  regions  that  are  thoroughly  in- 
fected. In  that  way  I  think  we  should  diminish  the  number  that 
are  to  be  killed  in  the  spring,  and  that  at  small  cost. 

Professor  FERNALD.  In  reply  to  that,  Professor  Riley  has 
already  expressed  his  opinion.  A  year  ago  I  had  just  the  same 
opinion  that  Professor  Riley  has,  and  expressed  it  to  the  commis- 
sioners, but  they  had  alread}7  gone  to  work.  I  talked  with  some 
entomologists  about  it,  and  they  differed  from  me ;  they  thought 
it  was  beneficial  to  use  other  means  than  Paris  green.  Theoreti- 
cally it  seems  to  me  that  any  other  means  would  be  a  needless 
expenditure  of  money,  and  Professor  Riley's  suggestion  to  exter- 
minate them  in  one  year  would  be  a  good  one  if  it  could  be  accom- 
plished ;  but  I  question  whether  it  would  be  wise  for  us  to  go 
from  this  meeting  to  the  Legislature  with  that  proposition.  If 
you  failed  to  do  it  in  one  year  and  came  back  for  a  second  appro- 


APPENDIX.  xi 

priation,  you  might  find  it  difficult  to  get  it.  This  is  merely  a 
policy  suggestion.  I  can  conceive  that,  even  with  the  most  thor- 
ough work  that  can  be  done  with  Paris  green  in  spraying  trees,  a 
few  might  escape  and  start  a  new  colony.  Then  in  another  twenty 
years  this  thing  would  come  up  again. 

Professor  SHALER.  Do  you  gentlemen  agree  that  we  must  look 
forward  to  a  careful  and  continuous  work  against  this  moth  ? 

Professor  RILEY.  As  I  said  before,  we  have  nothing  to  do 
with  the  experience  or  methods  of  Europe,  where  the  insect  pre- 
vails over  vast  areas,  and  where  nobody  expects  to  exterminate 
it.  Yet  there  have  been  instances  of  similar  extermination,  as, 
for  instance,  what  the  Prussian  government  did  with  the  potato 
beetle ;  and  here  you  have  an  opportunity  to  show  that  you  can 
stamp  this  thing  out.  I  expect  a  few  will  escape.  That  is  why 
I  made  the  suggestion  that  it  would  be  wise  to  introduce  such  par- 
asites as  can  be  used  against  it,  with  a  view  of  permitting  them 
to  search  out  those  which  may  have  escaped.  The  matter,  as  I 
said,  may  not  be  possible  ;  but,  if  it  is,  it  is  only  possible  in  that 
way,  and  all  other  efforts  would,  I  think,  be  rather  puerile,  and 
serve  to  bring  the  whole  thing  into  popular  disfavor.  Set  the 
school-boys  to  work  on  the  eggs ;  that  is  good  as  a  prophylactic 
measure,  and  would  do  a  certain  amount  of  good,  but  the  good 
would  be  very  slight  as  compared  with  the  effective  work  you 
ought  to  do  in  the  actual  destruction  of  the  caterpillars.  As  I 
said  before,  the  fact  that  the  insect  has  been  diminished  in  num- 
bers would  be  rather  against  the  efficient  extermination  of  the 
larvae  in  summer,  for  the  reason  that  it  is  harder  to  find  an  isolated 
bunch  of  caterpillars  in  a  county  than  when  they  are  numerous. 
I  still  hold  to  the  belief  that  whatever  funds  the  Legislature  can 
give  you  should  be  devoted  to  a  prompt  and  effective  attempt 
at  stamping  out. 

Professor  SHALER.  Suppose  every  tree  sprayed,  what  reason 
have  we  to  believe  that  we  should  have  disposed  of  the  pest? 

Professor  RILEY.  There  would  be  need  for  some  years  after- 
ward of  the  greatest  care.  I  would  not  attempt  to  kill  the  young 
caterpillars ;  wait  until  they  are  somewhat  advanced,  so  that  the 
work  could  be  concentrated  within  a  narrow  limit  of  time. 

[At  this  point  Mr.  Scudder  came  in.] 

Professor  SHALER.  The  discussion  has  been,  Mr.  Scudder,  on 
the  question  as  to  whether  it  would  be  well  to  proceed  at  once  to 
the  destruction  of  the  eggs.  There  are  places  where  the  eggs  are 
abundant,  and,  as  we  know,  they  are  conspicuous,  and  it  seems 
that  between  now  and  hatching  time  we  might  collect  a  consider- 
able per  cent,  of  them,  paying  for  them  by  weight  or  measure, 


xii  THE   GYPSY  MOTH. 

and  at  once  destroying  them.  Professor  Riley  thinks  that  would 
dimmish  the  conspicuousness  of  the  colonies,  so  to  speak,  and 
make  it  harder  to  find  them,  and  thinks  that  an  equal  amount  of 
money  would  go  further  in  poisoning  with  spray  than  it  would  in 
collecting  the  eggs.  I  should  like  to  hear  from  Mr.  Scudder 
what  he  thinks  about  the  desirableness  of  doing  anything  with  the 


Mr.  SCUDDER.  I  feel  that  I  have  no  right  to  speak  in  the 
presence  of  others  here  who  have  given  special  study  to  economic 
entomology,  while  I  have  not.  All  I  can  speak  upon  is  the 
natural  history  of  the  moth,  and  on  that  side  of  the  question  it 
might  be  well  to  ask  whether  it  is  behaving  the  same  in  this 
country  as  in  the  old  country.  There  are  a  number  of  moths 
single-brooded  in  the  old  country  which  are  double-brooded  here. 

Professor  RILEY.     I  have  assumed  that  it  was  single-brooded. 

Professor  FEKNALD.  I  have  bred  it  twice,  two  years  in  succes- 
sion. 

Mr.  SCUDDER.  If  it  is  single-brooded,  there  is  this  point  to  be 
brought  out,  that,  as  the  caterpillar  is  a  very  liberal  feeder,  so,  of 
course,  it  is  very  much  more  difficult  to  reach  by  spraying,  because 
the  spraying  is  not  to  be  confined  to  a  few  kinds  of  trees,  but  to  a 
very  large  number,  so  that  one  would  say  you  would  have  to  spray 
almost  everything  you  came  across.  So  with  the  eggs,  which  are 
laid  not  always  on  trees,  but  on  almost  anything  else.  It  there- 
fore becomes  the  most  dangerous  insect  enemy  we  have  had  for  a 
long  time,  I  think.  If  it  is  single-brooded,  it  seems  to  me  that 
nature  has  indicated  the  easiest  means  of  attack.  The  eggs  are 
laid  in  batches,  and  are  exposed  for  eight  months  of  the  year. 
Therefore  it  seems  to  me  that  the  egg  is  the  place  to  attack.  I 
should  suppose  that  the  same  amount  of  money  expended  in  the 
destruction  of  the  eggs  would  effect  a  very  much  larger  end  than 
the  same  amount  of  money  spent  in  spraying. 

Professor  RILEY.  I  have  been  trying  to  bring  out  what  knowl- 
edge there  is  as  to  the  actual  range  of  the  insect,  and  my  remarks 
on  the  possibility  of  stamping  it  out  have  all  been  based  on  that. 
I  want  to  say  that  if  the  insect  has  spread  beyond  the  limits  in- 
dicated by  Professor  Shaler,  and  got  into  the  larger  trees,  I  think 
the  question  of  stamping  it  out  a  very  doubtful  one.  At  the  same 
time  there  is  an  opportunity  here  for  the  State  of  Massachusetts  to 
make  the  experiment,  and  show  what  can  be  done  by  efficient 
means  and  intelligence.  I  would  rather  offer  a  higher  bounty  to 
every  school-boy  for  pointing  out  where  the  caterpillars  are  to  be 
found  during  two  weeks  in  June,  than  for  gathering  the  eggs.  I 
believe  that  there  is  a  chance  of  stamping  it  out,  if  it  is  not 


APPENDIX.  xiii 

beyond  the  region  where  the  trees  are  comparatively  few  in  num- 
ber and  not  very  large. 

Professor  SHALER.  How  would  it  do,  as  one  of  the  early  steps 
in  this  work,  to  get  all  the  information  we  can  as  to  the  periphery, 
and  publish  maps  showing  it  ?  Let  us  ask  for  information  as  to 
the  spread  of  the  pest  beyond  those  limits.  I  should  hesitate 
about  offering  a  reward  for  the  location  of  the  caterpillars,  because 
there  is  the  possibility  of  the  school-boys  planting  them.  A 
reward  for  the  eggs  is  much  more  easy,  and  we  could  probably 
interest  the  school-boys  in  searching  for  them  ;  but  it  would  hardly 
do  to  offer  a  reward  which  might  serve  to  spread  the  plague.  All 
these  rewards  for  animals  are  very  dangerous. 

Professor  RILEY.  On  general  principles  it  is  bad  policy,  but 
the  same  objection  would  apply  to  a  reward  for  the  eggs.  If  the 
boys  once  learned  that  they  could  get  a  certain  amount  of  money 
for  the  eggs,  they  would  not  be  so  interested  in  exterminating  them, 
and  thus  cutting  off  future  revenue. 

Professor  SHALER.  I  should  state  a  definite  reward,  and  not  go 
beyond  a  certain  time. 

Mr.  CRAIG.  We  have  two  or  three  village-improvement  associa- 
tions especially  to  take  care  of  the  trees.  We  extended  an 
invitation  to  the  citizens  to  take  part  in  the  work,  and  they  were 
to  notify  certain  committees  wherever  they  found  any  eggs.  This 
was  done  to  a  large  extent,  and  I  think  it  aided  the  commissioners 
very  largely  in  finding  out  where  the  moths  were. 

Professor  SHALER.  You  can  tell  us  about  the  extent  of  the  pest 
in  Medford.  Over  about  how  large  a  territory  did  it  extend? 

Mr.  CRAIG.  More  or  less  from  the  Maiden  line  over  to  Arling- 
ton. 

Professor  SHALER.  About  a  mile  and  a  half  in  the  worst- 
infested  district. 

Professor  EILEY.  What  was  the  result  of  the  commission's 
work?  Are  the  eggs  found  abundantly  in  that  neighborhood? 

Mr.  CRAIG.  I  don't  believe  there  are  one-tenth  the  eggs  there 
were  when  the  commission  commenced. 

Professor  RILEY.  What  was  the  result  of  the  commission's  work 
last  year?  Was  it  appreciable  on  the  number  of  eggs  known  to 
have  been  there? 

Mr.  CRAIG.  Yes,  certainly.  I  differ  from  you  two  gentlemen 
about  destroying  the  eggs.  I  think  it  was  the  means  of  destroy- 
ing a  great  many  of  the  pests.  On  many  trees  they  were  con- 
trolled by  gathering  the  eggs. 

Mr.  SESSIONS.  I  have  no  scientific  knowledge  on  the  subject, 
but  it  seems  to  me  the  first  and  most  important  thing  we  have  to 


xiv  THE  GYPSY  MOTH. 

do  is  to  find  the  outside  line,  even  if  we  don't  do  any  more  than 
that  in  one  season.  The  old  commissioners  claim  that  they  have 
found  it ;  our  first  business  should  be  to  verify  that. 

Professor  SHALER.     Did  they  make  a  map  ? 

Mr.  SESSIONS.     I  think  not. 

Mr.  SCUDDER.  How  do  they  know  the  moth  wasn't  blown  fifty 
miles  away  by  a  storm  ? 

Professor  SHALER.  It  may  have  been  ;  but  it  is  a  strong  point 
in  our  favor  that  after  the  creature  has  been  twenty  years  on  the 
scene  it  still  has  a  tolerably  distinct  periphery. 

Professor  RILEY.  That  is  what  I  have  based  my  recommenda- 
tion to  exterminate  it  on.  I  should  not  like  to  see  the  attempt 
abandoned,  but  my  remarks  have  all  been  made  with  a  view  of 
economizing  means  and  time  in  one  effective  effort  to  exterminate 
it.  All  these  other  measures  will  come  in  if  we  have  to  deal  with 
the  pest  as  a  permanent  thing  among  us.  As  a  mere  State  meas- 
ure, with  a  view  to  not  having  the  unenviable  reputation  of  having 
given  a  pest  to  the  rest  of  the  country  or  done  nothing  to  prevent 
its  spread,  Massachusetts  has  an  excellent  opportunity  of  showing 
what  may  be  done  by  intelligent,  concentrated  effort.  All  other 
means  are  puerile  as  compared  with  destruction  by  the  arsenicals. 
All  other  means  are  now  abandoned  in  fighting  the  canker-worm, 
the  codling  moth  and  some  other  insects,  and  intelligent  spraying 
at  the  proper  time  has  come  to  be  looked  upon  as  the  most  efficient 
means  of  protection  against  these  insects.  My  idea  is  that  what 
you  ought  to  do  is  to  employ  a  sufficient  force  of  intelligent  per- 
sons to  scour  that  whole  region  in  the  month  of  June,  and  indicate 
every  plant  that  has  a  brood  upon  it. 

Professor  SHALER.  Suppose  you  had  a  hundred  persons  search- 
ing at  the  same  time,  what  general  instructions  could  you  give 
them  in  determining  what  trees  were  infested  ? 

Professor  RILEY.  The  insect  is  gregarious,  and  therefore  con- 
spicuous. There  is  no  reason  why  intelligent  search  should  not 
detect  it,  even  on  the  highest  trees. 

Professor  SHALER.  How  much  time  could  you  reckon  on  hav- 
ing for  your  search  after  the  creature  came  out? 

Professor  RILEY.  I  should  say  you  could  count  on  ten  days 
after  it  was  hatched.  Its  gregarious  nature  makes  that  feasi- 
ble. 

Professor  SHALER.  How  much  time  is  there  before  it  begins  to 
spin? 

Professor  RILEY.     I  believe  it  takes  three  or  four  weeks. 
Professor  FERNALD.     I  think  it  highly  desirable  to  make  the 
attempt  to  stamp  it  out.     I  don't  know  that  it  can  be  done,  but  it 


APPENDIX. 


xv 


is  worth  trying.  If  we  cannot  exterminate  it,  the  other  excellent 
remedies  can  be  used  for  holding  it  in  check. 

Professor  SHALER.  Had  we  not  better  wait  until  we  can  strike 
a  hard  blow,  and  do  the  best  we  can  this  year  with  prevention  ? 

Professor  RILEY.  I  am  strongly  of  opinion  that  you  had  better 
not  wait.  Some  contingencies  may  arise  to  give  it  a  sudden 
impetus.  I  would  adopt  the  auxiliary  methods  of  introducing 
parasites,  etc.,  and  I  would  also  have  a  special  committee  author- 
ized to  inspect  all  nursery  stock  that  goes  out  from  the  infested 
region,  and  not  allow  it  to  go  until  passed  upon  by  competent 
men. 

Professor  FERNALD  thought  the  Federal  government  might  take 
charge  of  the  work.  Professor  RILEY  stated  that  he  would  be  glad 
to  assist  in  any  way  possible,  but  that  since  the  establishment  of 
State  experiment  stations  the  Federal  government  felt  it  had  no 
further  function  in  the  States,  so  far  as  local  insects  are  concerned. 
Professor  SHALER  thought  the  State  of  Massachusetts  should  make 
the  fight  itself,  and  only  ask  for  Federal  aid  in  case  it  could  not 
exterminate  the  pest.  Twenty-four  thousand  dollars  were  on  hand, 
and  he  thought  that  twenty-five  thousand  dollars  or  fifty  thousand 
dollars  more  could  be  counted  on  from  the  Legislature. 

Mr.  SCUDDER.  I  don't  understand  the  force  of  the  arguments 
used  by  my  neighbors  on  either  side  [Professors  Riley  and  Fernald] 
of  delaying  the  work  by  not  taking  the  eggs  at  present.  Why  do 
they  want  all  the  caterpillars  out  that  they  can  get,  in  order  to  ex- 
terminate them? 

Professor  SHALER.     It  is  a  question  of  seeing  them,  I  believe. 

Mr.  SCUDDER.  I  understand.  But,  if  you  destroy  so  many 
eggs  that  say  only  one  tree  out  of  five  is  attacked,  you  have  to 
deal  with  only  one-fifth  as  many  trees  in  spraying. 

Professor  RILEY.  I  want  to  tell  Mr.  Scudder  just  why  I  rather 
urge  the  policy  I  have  advised.  First  of  all,  it  is  from  the  politi- 
cal side.  If  you  ask  for  an  appropriation  to  stamp  it  out,  you 
must  do  your  best  to  stamp  it  out.  As  Professor  Fernald  has 
suggested,  it  is  simply  a  question  of  means,  and  I  would  not  think 
of  asking  for  less  than  one  hundred  thousand  dollars,  and  I  would 
concentrate  that  where  it  would  do  the  most  good.  Killing  the 
eggs  is  frittering  the  money  away  at  a  time  when  it  is  not  of  so 
much  value  as  if  concentrated.  Secondly,  I  have  little  faith  in  the 
destruction  of  eggs  in  this  case,  where  they  are  laid  on  so  many 
different  objects.  I  remember  distinctly  a  little  cedar  tree  not 
more  than  six  feet  high  in  my  own  grounds  that  was  attacked  by 
the  bagworm.  I  thought  I  would  see  whether  I  could  not  clear 
them  off.  I  worked  for  two  consecutive  months  picking  off  from 


xvi  THE  GYPSY  MOTH. 

the  tree  the  issue  of  not  more  than  two  females.  Almost  daily  I 
went  to  that  tree,  and  found  fresh  specimens  that  I  had  overlooked 
the  day  before.  Yet  in  the  Smithsonian  grounds  I  have  absolutely 
stopped  similar  injury  on  larger  trees  in  a  few  minutes  by  spraying. 
It  would  have  been  no  use,  in  my  judgment,  to  have  attempted  to 
eradicate  them  by  hand  picking.  Suppose  you  have  somebody 
climb  a  tree  and  gather  twelve  batches  of  eggs,  but  he  fails  to  get 
the  thirteenth.  It  will  cost  no  more  to  spray  a  tree  for  the  thirteen 
batches  than  it  will  for  the  one. 

Professor  SHALER.  When  I  came  here  I  was  strongly  in  favor 
of  offering  a  reward  for  the  eggs,  but  I  admit  I  am  shaken  now. 

Mr.  SCUDDER.  I  don't  think  you  can  get  sufficient  force  to  spray 
the  trees  thoroughly  in  the  time  allowed. 

Professor  SHALER.  I  think  we  shall  have  to  ask  the  Agricultural 
College  to  lend  us  say  eighty  or  a  hundred  of  their  young  men  for 
this  work. 

Mr.  SESSIONS.  There  are  many  people  living  in  the  neighbor- 
hood of  this  spraying  who  claim  that  it  was  of  no  sort  of  value. 
Do  any  of  these  gentlemen  believe  that? 

Professor  RILEY.  I  think  the  reasons  that  have  been  given  ex- 
plain why  they  had  that  experience.  It  was  simply  due  to  the 
impurity  of  the  Paris  green  and  the  imperfect  manner  of  applying 
it.  You  will  always  have  more  or  less  of  failure  until  you  put  this 
matter  into  the  hands  of  men  who  can  give  their  whole  time  to  it 
during  that  period.  Only  those  men  should  be  employed  who 
have  ability  and  experience ;  and  one  man,  particularly,  should  be 
engaged  to  superintend  the  whole  work,  and  as  many  other  com- 
petent persons  as  possible. 

A  tree  fifty  feet  high  is  very  easily  sprayed.  If  the  caterpillars 
could  not  be  killed  by  spraying,  it  would  be  better  to  cut  the  trees 
down  over  the  whole  of  the  Middlesex  Fells.  It  pays  better  to 
make  one  grand  effort  than  to  fritter  your  energies  away  over  a 
number  of  years,  and  then  fail.  The  Board  in  control  of  the 
work  should  control  everything.  If  Paris  green  is  used,  it  should 
all  be  issued  by  the  Board,  after  being  tested. 

Professor  SHALER.  I  should  like  to  ask  your  opinion,  gentle- 
men, whether  any  considerable  risk  to  health  is  to  be  apprehended 
from  this  large  use  of  arsenic  in  the  country.  Is  there  any  risk  of 
poisoning  the  water  or  of  poisoning  animals  or  men  ? 

Mr.  APPLETON.  The  committee  on  public  health  is  having  an 
extended  hearing  on  the  use  of  arsenicals. 

Professor  RILEY.  If  the  spraying  is  copious  and  careless, 
which  is  unnecessary,  there  is  danger  of  stock  feeding  upon  grass 
which  has  been  so  impregnated,  but  there  is  no  necessity  for  that. 


APPENDIX.  xvii 

The  spraying  should  be  of  such  a  character  that  there  would  be 
comparatively  little  falling  from  the  tree  or  shrub  sprayed. 

Professor  SHALER.  Have  you  known  of  any  cases  of  poisoning 
in  persons  employed  in  spraying  ? 

Professor  RILEY.  No",  I  have  seen  none,  but  I  have  known  of 
cases  where  negroes  would  sit  on  the  back  of  a  mule  with  spray- 
ing pumps,  going  through  cotton  fields,  and  carelessly  allow  the 
water  to  fall  on  them.  I  have  known  them  to  become  sore  in  the 
groin,  but  never  knew  of  a  fatal  case. 

Mr.  APPLETON.  The  spraying  is  washed  off  by  the  first  rain, 
of  course? 

Professor  RILEY.  It  should  not  be.  The  whole  tree  is  en- 
shrouded in  a  vapor  which  is  all-sufficient,  and  which  is  more 
effective  than  a  more  copious  spraying. 

Professor  SHALER.  Is  there  any  particular  form  of  engine 
which  will  give  that  form  of  spraying? 

Professor  RILEY.  There  are  various  spraying  devices  in  use, 
depending  largely  on  the  height  of  the  vegetation.  If  you  want 
to  throw  to  any  great  height  without  the  use  of  ladders,  you  need 
a  spraying  device  that  will  throw  a  strong  jet.  In  almost  all 
cases  you  can  use  the  cyclone  nozzle  in  its  Vermorel  modification. 

Mr.  SCUDDER.  I  should  like  to  say  before  going  that  it  does 
not  seem  ty  me  likely  that  the  thing  will  be  exterminated,  but 
that  it  can  be  held  in  check  for  many  years.  The  reason  why  I 
don't  think  it  can  be  exterminated  is  because  we  have  not  enough 
persons  used  to  looking  for  the  caterpillars  to  examine  the  trees 
and  say  for  certain  that  there  are  none  there.  I  do  think,  how- 
ever, that  it  can  be  held  in  check. 

Selectman  W.  A.  PEIRCE  of  Arlington  said  they  had  very  little 
trouble  with  it  in  his  neighborhood.  The  sentiment  of  the  people 
there  was  in  favor  of  the  continuation  of  the  work. 

Mayor  WIGGIN  of  Maiden.  "We  went  through  and  marked 
every  tree  that  was  infested,  and  then  went  through  again  and 
sprayed  them.  The  trees  were  not  so  infested  as  to  be  particu- 
larly noticeable. 

Mr.  GOULD  of  Melrose.  The  selectmen  did  not  believe  there 
were  any  gypsy  moths  in  their  town.  As  far  as  he  knew,  the 
people  were  not  disturbed  by  their  presence.  They  would  be 
glad,  however,  to  have  the  inspectors  go  through  the  town  and 
look  for  it,  and  would  gladly  second  their  efforts. 

Professor  SHALER.  I  think  it  would  be  a  tax  of  probably  more 
than  one  hundred  thousand  dollars  annually  if  not  checked. 

Professor  RILEY.  There  is  no  question  of  that,  if  it  is  allowed 
to  take  its  course.  That  is  what  makes  it  so  vitally  interesting  to 


xviii  THE   GYPSY  MOTH. 

me,  and  why  I  am  so  impatient  of  any  efforts  to  simply  check  it. 
I  have  nothing  to  say  about  checking  it ;  I  speak  for  stamping  it 
out.  Mr.  Scudder  simply  says  he  doesn't  think  it  will  be  exter- 
minated. As  to  how  much  of  any  given  territory  one  individual 
is  capable  of  critically  examining,  a  man  who  is  capable  of  dis- 
tinguishing between  this  caterpillar  and  others,  doing  nothing 
else,  would,  in  my  judgment,  be  able  easily  to  go  over  a  square 
mile  of  ground  a  day,  except  in  dense  forest. 

Professor  SHALER.  I  don't  think  so ;  nothing  like  it.  If  the 
work  was  done  closely  (and  two  together  would  do  better  work 
than  one),  my  impression  is  they  would  be  doing  good  work  to 
get  over  a  hundred  acres  a  day. 

Professor  RILEY.    "Well,  say  a  hundred  acres  — 

Professor  SHALER.  If  we  could  get  from  the  college  say  forty 
young  men  as  inspectors,  we  would  have  four  thousand  acres  a  day 
inspected,  and  my  impression  is  that  the  region  covers  about  ten 
thousand  acres.  That  area  can  be  thoroughly  inspected  by  twenty 
parties  of  selected  men  doing  nothing  else.  They  should  mark 
the  infested  trees  and  plat  them  on  a  map.  As  we  are  no  longer 
a  paid  commission,  I  would  devote  that  money  to  experts.  We 
want  the  best  expert  we  can  select  to  superintend  the  actual  appli- 
cation of  the  remedies.  When  a  tree  is  marked  as  infested,  let  it 
be  numbered  so  and  so ;  and  when  it  is  sprayed,  let  an  account 
be  taken  of  that  tree,  so  that  by  some  system  of  checking  we  can 
find  whether  every  tree  has  been  disposed  of  or  not. 

Professor  RILEY.  The  suggestion  seems  to  me  eminently  wise. 
But  I  suppose  you  could  get  the  leading  citizens  in  a  community 
interested  also? 

Mr.  SESSIONS.  I  don't  believe  you  can  get  the  college  boys  to 
come. 

Professor  RILEY.  Not  if  you  paid  them  ?  It  would  be  an  ex- 
cellent education  for  agricultural  students ;  and  if  you  offered 
them  a  hundred  dollars  each,  you  would  have  no  difficulty  in  get- 
ting them,  I  think. 

Professor  SHALER.     What  month  should  the  work  be  done  in? 

Professor  RILEY.  As  far  as  I  can  learn,  the  month  of  June.  I 
believe  that  about  the  second  week  in  June  will  be  the  time  to 
strike,  after  having  made  all  your  plans,  got  your  forces  ready  and 
trained  your  men.  It  may  be  that  the  thing  is  not  practicable, 
but  I  can  see  nothing  impracticable.  It  is  simply  a  question  of 
money  and  men.  After  this  one  thorough  effort  you  need  not  ask 
for  another  appropriation ;  everybody  will  be  interested,  and  then 
you  could  afford  to  offer  a  big  reward  for  any  eggs  that  might  es- 
cape. The  attempt  is  well  worth  making. 


APPENDIX.  xix 

Mr.  SESSIONS.  A  great  obstacle  is  in  procuring  help  you  can 
depend  on. 

Professor  RILEY.  Let  me  make  one  other  suggestion.  While 
the  infested  area  is  stated  in  the  rough  at  fifty  square  miles,  from 
what  Professor  Shaler  said  there  would  probably  be  large  portions 
of  it  that  would  require  nothing  but  inspection.  Now,  wherever 
there  are  large  trees  difficult  to  climb,  I  would  certainly  take  the 
precaution  to  ring  or  band  them,  because  that  will  prevent  any 
stray  caterpillars  from  climbing  up  those  trees.  No  caterpillars 
will  ascend  'such  trees ;  and  if  any  escape,  you  will  find  them  at 
the  foot  of  the  trees.  European  experience  shows  this. 

Professor  SHALER.  Where  can  we  get  on  the  track  of  the  mixt- 
ure they  use  in  Europe  for  that  purpose  ? 

Professor  RILEY.  You  can  use  printers'  ink  for  that  purpose. 
In  Newark  I  recommended  the  use  of  the  fire  department  for 
spraying  certain  very  tall  elm  trees. 

Professor  SHALER.  I  presume  we  could  make  such  an  arrange- 
ment with  the  fire  departments. 

Mr.  CRAIG.     We  have  an  engine  that  could  be  so  used. 

Professor  RILEY.  I  would  modify  my  objection  to  egg  collect- 
ing just  so  far  that  in  the  case  of  large  trees  it  would  be  advisable 
to  do  the  work  prior  to  aestivation.  I  think  boys  could  go  over 
them,  and  in  this  direction  winter  work  would  be  advisable.  It 
would  also  be  advisable  to  have  these  large  trees  very  carefully 
inspected  for  the  eggs ;  but  I  do  not  believe  you  would  be  justified 
in  attempting  to  destroy  the  eggs  over  the  whole  area. 

Professor  SHALER.  Is  the  energy  of  diffusion  and  the  tendency 
of  the  females  to  travel  at  all  proportioned  to  their  numerousness  ? 

Professor  RILEY.  Yes ;  it  is  a  general  principle  with  insects 
that,  in  proportion  as  they  become  unduly  multiplied,  the  migra- 
tory instinct  is  developed. 

Professor  SHALER.  So  that,  in  so  far  as  we  reduce  the  number 
in  a  given  field,  we  tend  to  reduce  the  expansive  energy? 

Professor  RILEY.     Without  doubt. 

Professor  SHALER.  And,  therefore,  if  we  fail  to  exterminate  it 
this  year,  we  shall  at  least  diminish  its  expansive  energy. 


THE  GYPSY  MOTH. 


APPENDIX    B. 


REVISED  RULES  AND  REGULATIONS  ADOPTED  BY  THE  STATE 
BOARD  OF  AGRICULTURE, 

UNDER  CHAPTER  210,  ACTS  OF  1891. 

RULES  AND  REGULATIONS  FOR  THE  PUBLIC. 

1.  All  persons  are  forbidden  by  law  to  remove  the  eggs  or 
any  other  form  of   the  gypsy  moth  from  one  city  or  town  to 
another,  and  are  requested  to  exercise  care  against  so  transport- 
ing the  gypsy  moth  on  teams  and  carriages. 

2.  All  persons  are  forbidden  to  remove  from  any  locality  in 
the  towns  of  Medford,  Everett,  Chelsea,  Maiden,  Melrose,  Cam- 
bridge, Winchester,  Somerville  and  Arlington  any  hay,  manure, 
wood,  bark,  trees,  rags,  lumber  or  shrubbery  of  any  kind,  without 
a  written  permit  from  the  Board  of  Agriculture.     Persons  desiring 
to  remove  such  materials  will  notify  the  field  director,  13  Stan- 
wood  Hall,  Maiden. 

3.  All  persons  are  forbidden  to  in  any  way  imitate  or  erase  the 
marks  employed  by  this  Board  to  designate  trees,  fences  or  build- 
ings which  are  infested  or  have  been  cleaned. 

4.  All   vehicles    leaving    the   above-named   district    may   be 
stopped  by  the  officers  of  the  Board  and  delayed  until  their  con- 
tents have  been  sufficiently  inspected  to  determine  the  fact  that 
they  are  not  liable  to  transport  the  eggs  or  any  other  form  of  the 
insect. 

5.  No  person  shall  trim,  scrape  or  cut  down  trees  within  the 
district  known  to  be  infested  by  the  gypsy  moth,  or  remove  them 
without  first  notifying  this  Board,  and  having  said  trees  thoroughly 
inspected,  and,  if  found  infested,  cleaned  under  its  direction. 

The  eggs  of  the  gypsy  moth  are  frequently  scattered  abroad  by 
scraping  the  trees  and  by  careless  gathering ;  therefore,  all  per- 
sons except  the  authorized  agents  of  this  Board  are  forbidden  to 
remove  the  eggs  of  the  gypsy  moth  from  the  trees  or  other  objects 
upon  which  they  may  have  been  deposited,  or  to  remove  such 
infested  trees  or  objects  from  one  place  to  another. 

Land  owners  and  tenants  are  requested  to  destroy  all  other 
forms  of  the  moth  which  they  may  find  upon  their  premises. 


APPENDIX.  xxi 

6.  All  persons,  upon  notice,  are  required  to  confine  their  dogs 
while  the  agents  of  this  Board  are  at  work  upon  their  premises. 

7.  Owners  or  tenants  are  requested  to  gather  and  burn  all 
rubbish  and  useless  material  upon  their  premises  that  may  provide 
nesting-places  for  the  gypsy  moth,  and  to  fill  with  cement  or  other 
solid  material  all  holes  in  trees  upon  their  premises. 

8.  All  persons  are  requested  to  keep  the  windows  of  their 
houses  protected  by  screens  during  the  summer  months,  as  the 
moth  often  lays  its  eggs  in  houses,  wherever  it  can  gain  admittance. 

9.  All   persons  having  reasonable  cause  to  believe  that   the 
eggs,  caterpillars  or  other  forms  of  the  gypsy  moth  exist  on  or 
about  their  premises  are  earnestly  requested  to  forthwith  notify 
E.  H.  Forbush,  director,  by  letter  addressed  to  his  office  in  Mai- 
den, Mass.     Information  of  the  moth's  existence  in  isolated  or 
unsuspected  localities  will  be  gratefully  received,  and  all  persons 
furnishing  such  information  will  receive  the  thanks  of  the  Board. 

10.  Notice  is  hereby  given  that  it  will,  in  some  cases,  be  nec- 
essary to  remove  boards  from  fences  or  buildings.     In  all  cases 
such   boards   will   be   eventually   replaced,    if   possible,    without 
damage  to  the  structure.     Attention  is  called  to  the  fact  that  any 
damage  done  by  the  agents  or  servants  of  this  Board,  in  the  work 
of  exterminating  the  moth,  may  be  recovered  under  provisions  of 
section  2,  as  above  printed.* 

Attention  is  also  called  to  section  6,  as  above  printed,*  which 
sets  forth  the  penalties  for  obstructing  any  servant  or  agent  of  the 
State  Board  of  Agriculture  under  this  act. 

11.  Courteous   and   considerate   conduct   is   expected   of   all 
agents  and  employees  of  the  Board.     Complaints  in  writing  con- 
cerning any  infraction  of  this  rule  should  be  sent  to  the  director, 
and  will  be  heard  by  him  or  the  committee. 

E.  W.  WOOD, 
AUGUSTUS  PRATT, 

F.  W.  SARGENT, 
J.  G.  AVERT, 

S.  S.  STETSON, 
WM.  R.  SESSIONS, 
Committee  of  the  State  Board  of  Agriculture. 

RULES  AND  REGULATIONS  FOR  AGENTS  AND  EMPLOYEES. 
It  shall  be  the  duty  of  employees  to  familiarize  themselves  with 
the  rules  governing  the  gypsy-moth  work.     The  violation  of  any 
of  the  rules  will  be  sufficient  cause  for  discharge  at  any  time  with- 
out notice. 

*  See  page  47. 


xxii  THE   GYPSY  MOTH. 

General  Rules. 

1.  No  person  will  be  employed  or  retained  who  is  known  to 
use  intoxicating  liquors  as  a  beverage. 

2.  Smoking  is  strictly  prohibited  during  hours  of  labor. 

3.  Courteous  and  considerate  conduct  is  required  of  all  agents 
and  employees  of  this  Board. 

4.  All  agents  and  employees  (unless  otherwise  ordered  by  the 
director)  must  wear  at  all  times  during  working  hours  the  uniform 
caps  and  badges  issued  by  the  quartermaster. 

5.  Employees  must  provide  themselves  with  the  uniform  pre- 
scribed by  the  State  Board  of  Agriculture  and  said  uniform  must 
be  worn  during  working  hours. 

6.  No  employee  shall  sign  the  pay-roll  for  another  unless  he 
has  a  written  order  from  the  person  for  whom  he  signs.     Said 
order  must  be  made  out  on  one  of  the  blanks  furnished  by  the 
Board  and  must  be  sent  with  the  pay-roll  to  the  director's  office. 

7.  Superintendents  and  inspectors  are  empowered  to   recom- 
mend men  for  employment,  promotion  or  discharge.     Delinquents 
should  be  sent  with  a  sealed  note  of  explanation  to  the  office. 

8.  If  an  employee  is  unsatisfactory  in  any  way,  the  inspector 
or  other  officer  immediately  in  authority  over  him  should  inform 
him  at  once  of  the  fact  and  note  it  on  the  report  of  that  day. 

9.  If  men  are  delayed  in  getting  to  work  by  the  lateness  or 
negligence  of  an  inspector  or  a  teamster,  or  if  any  inspector  shall 
order  or  allow  his  men  to  cease  work  before  the  regular  hour,  said 
inspector  or  teamster  will  have  the  hours  lost  by  himself  and  the 
men  deducted  from  his  time,  and  superintendents  shall  report  the 
facts  of  the  case. 

10.  Employees  before  signing  receipts  for  tools  should  assure 
themselves  that  the  numbers  on  the  tools  and  receipts  agree. 

11.  If  a  transfer  of  tools  from  one  employee  to  another  is  made 
in  the  field,  the  tools  will  remain  charged  to  the  man  who  took 
them  from  the  storehouse,  unless  a  record  of  such  transfer  is  taken 
in  or  mailed  to  the  office  within  twenty-four  hours  of  the  time  of 
such  transfer.     Unless  such  notice  is  received,  the  employee  to- 
whom  the  tools  were  originally  charged  will  be  held  responsible 
for  them. 

12.  Inspectors  may  use   time   cards,   when  necessary,  as   a 
medium  for  ordering  tools. 

13.  Drivers  and  owners  of  wagons  are  responsible  fou  tools 
committed  to  their  charge. 

14.  An  employee  leaving  the  service  of  this  Board  must  at 
once  return  to  the  quartermaster  all  property  of  the  Commonwealth 


APPENDIX.  xxiii 

which  has  been  in  his  charge.     Otherwise,  the  full  value  of  the 
same  will  be  deducted  from  his  wages  then  due. 

Rules  for   Inspecting   Sections,   Marking   Trees  and   Destroying 
Eggs. 

15.  Each   inspector  must   keep   in   his  note-book  a  complete 
record  of  all  work  done  in  his  section.     This  book  is  to  be  returned 
to  the  director's  office  when  called  for,  and  to  be  left  there  when 
the  inspector's  term  of  office  expires. 

16.  Each  inspector  must  carry  his  section  map  with  him  in  the 
field  and  locate  upon  the  map  (by  means  of  such  marks  as  may 
be  ordered  by  the  director)  each  tree  or  locality  that  he  finds 
infested. 

17.  Each  tree  found  infested  must  be  at  once  marked  with  such 
characters  as  may  be  designated  by  the  director,  the  mark  to  be 
on  the  trunk  at  three  points  equidistant  from  each  other  and  five 
feet  from  the  ground. 

18.  When  a  tree  is  found  infested  which  has  been  marked  in  a 
previous  season,  the  new  mark  is  to  be  placed  two  inches  above 
each  of  the  latest  marks. 

19.  Each  object  on  which  egg-clusters  of  the  gypsy  moth  are 
found  in  "outside  towns"  must  be  marked  with  a  spot  of  white 
paint  the  size  of  a  ten-cent  piece,  this  spot  to  be  within  an  inch  of 
each  egg-cluster.     Egg-clusters  found  in  woodland  must  be  sur- 
rounded with  a  ring  of  white  paint. 

20.  No  trees  on  highways,  in  orchards  or  upon  grounds  about 
residences  are  to  be  cut,  burned  or  trimmed  unless  it  is  found  to 
be  actually  necessary.     In  every  case  where  a  large  branch  is  cut 
off  the  stump  must  be  covered  with  coal-tar.     Trees  must  not  be 
cut  down  unless  written  permission  is  obtained  of  the  owner,  or 
unless  it  is  so  ordered  by  the  director. 

21.  Each  inspector  will  pay  special  attention  to  the  trees  and 
shrubbery  along  the  lines  of  railroad  in  his  territory.     The  grounds 
around  railroad  stations  must  be  carefully  inspected. 

22.  Inspectors  are  not  to  call  at  the  office  except  to  leave  re- 
ports, or  unless  by  special  order  of  the  director. 

23.  Each  inspector  or  acting  inspector  having  chai-ge  of  two 
or  more  men  will  form  his  men  in  line  and  call  the  roll  at  seven 
A.M.  at  the  place  where  he  begins  work.      He  will  again  form 
them  in  line  and  call  the  roll  at  the  close  of  the  day's  work. 

24.  When  the  roll  is  called  at  night  inspectors  must  state  dis- 
tinctly to  their  men  the  point  at  which  they  will  call  the  roll  on 
the  following  morning,  and  any  employee  who  fails  to  answer  this 
roll-call  will  not  be  allowed  full  time. 


xxiv  THE   GYPSY  MOTH. 

25.  Employees  will  exercise  great  care  that  they  do  not  carry 
living  larvae  from  place  to  place  either  on  their  vehicles  and  cloth- 
ing or  in  any  receptacle. 

26.  When  employees  under  the  direction  of  an  inspector  are 
obliged  to  injure  or  destroy  any  property,  or  when  property  is 
accidentally  destroyed,  or  accidents  of  any  kind  occur,  the  facts 
must  be  reported  at  once  to  the  inspector,  and  he  must  make  a 
note  of  the  same  in  his  report,  giving  an  estimate  of  the  amount 
of  damage  done  and  names  of  all  witnesses. 

27.  Inspectors  must  note   (and  ask  their  men  to  note)   and 
state  in  their  reports  the  language  and  means  used  by  persons  ob- 
structing their  work. 

28.  When  troublesome  dogs  are  encountered  inspectors  may 
require  the  owners  to  confine  them,  under  penalty  of  the  law. 

29.  Employees  must  not  leave  ladders  standing  or  lying  by  the 
curbstone  in  the  street.     They  must  be  taken  down  when  not  in 
use   and  removed  to  some   safe  place.     Care  must  be  used  in 
handling  ladders  and  also  in  climbing  trees,  not  to  break  or  other- 
wise injure  the  branches. 

30.  Employees  must  exercise  great  care  in  blazing  trees.     The 
inner  bark  should  never  be  cut. 

Fires. 

31.  No  fires  shall  be  kindled  except  by  order  of  the  division 
superintendent. 

32.  Superintendents  will  demand  that  due  caution  is  observed 
in  the  kindling  and  management  of  fires.     They  will  see  that  the 
necessary  appliances  are  at  hand  for  the  management  and  extin- 
guishing of  all  fires  ordered  kindled.     Inspectors  in  charge  will  be 
held  responsible  for  the  proper  management  of  fires,  or  if  fires  are 
left  at  the  close  of  the  day's  work  without  being  extinguished. 

33.  No  fires  are  to  be  built  upon  sidewalks,  or  near  the  curb- 
stones in  the  streets. 

Spraying. 

34.  Inspectors  must  notify  pedestrians  not  to  walk  under  trees 
which  are  being  sprayed,  and  must  avoid  spraying  on  vehicles. 

35.  In  spraying  always  station  the  tank  to  windward  of  the 
sprayers,  so  that  the  spray  may  not  blow  over  it. 

36.  Before  beginning  work  on  an  estate  inspectors  must  re- 
quest occupants  to  take  clothing  from  lines,  close  windows  and 
remove    anything   that   may   by   any   possibility   be    injured    by 
spraying. 

37.  Employees  must  use  great  care  not  to  injure  lawns,  flower- 
beds, vegetable  gardens  or  other  property. 


APPENDIX.  xxv 

38.  Inspectors  are  to  handle  and  mix  poisons. 

39.  The  solution  in  the  tank  must  be  constantly  stirred  from 
the  time  it  is  first  mixed  until  the  tank  is  empty. 

40.  Tanks  must  be  fastened  on  the  wagons  in  such  a  way  that 
they  cannot  be  overturned. 

41.  If,  during  the  spraying,  a  tree  is  found  infested  and  un- 
marked, it  must  be  marked.     Each  time  a  tree  is  sprayed  it  must 
be  marked  with  three  round  dots,  the  size  of  a  ten-cent  piece,  the 
first  set  being  placed  five  feet  from  the  ground,  and  each  succeed- 
ing set  an  inch  above. 

42.  Inspectors  will  carefully  notice  the  effect  of  the  spraying 
and  record  the  same  in  their  daily  reports. 

43.  The  spray  thrown  on  the  trees  must  be  as  fine  as  possible. 

44.  Drivers  of  spraying  wagons,  when  at  work,  will  be  under 
the  direction  of  the  inspector  in  whose  section  they  are  employed. 
Each  inspector  will  keep  the  time  of  his  driver  and  report  the 
same. 

45.  Inspectors  must,  when  possible,  draw  water  from  the  stand- 
pipes.     When  hydrants  are  used  the  inspector  only  shall  open  and 
close  them,  exercising  great  caution  to  open  and  close  them  slowly, 
but  not  closing  them  so  tightly  as  to  prevent  opening. 

46.  At  morning  and  at  noon,  before  beginning  spraying,  each 
nozzle  must  be  turned  into  the  bottom  of  the  tank  and  a  full 
stream  pumped  for  five  minutes. 

Reports. 

47.  The  rating  of  superintendents  and  inspectors  will  be  based, 
not  only  on  the  quality  of  the  work  done  by  their  men,  but  on  the 
fulness  and  excellence  of  their  own  reports.     All  reports  must  be 
sent  to  the  director's  office  and  are  subject  to  his  approval.     Each 
inspector  must  make  out  his  report  daily  and  give  it  to  his  super- 
intendent, or  send  it  to  the  office  (by  mail  or  otherwise)  on  the 
following  day.     Observations  on  the  habits  of  the  insect  and  other 
items  of  interest,  and  any  statements  or  complaints  by  citizens, 
should  be  embodied  in  the  reports. 

48.  Superintendents  must  notice  whether  the  streets  are  re- 
ported in  their  proper  sections. 

49.  Inspectors  must  give  time  of    employees  on   each  day's 
report. 

50.  In  case  of  the  absence  of  an  employee  the  inspector  must 
give  the  reason  (when  known  to  him)  for  such  absence  on  the 
report  of  the  day  when  such  absence  occurs. 

51.  Inspectors  must  observe  the  printed  headings  on  reports 
and  fill  spaces  reserved  under  the  same. 


xxvi  THE   GYPSY  MOTH. 

52.  Inspectors  must  give  the  correct  street  and  number  of  each 
building  and  estate  inspected  and  the  full  name  of  the  property 
owner  or  tenant. 

53.  If  at  work  in  two  or  more  sections  in  a  day,  inspectors 
must  make  a  separate  report  for  each  section. 

54.  The  name  of  the  inspector,  if  at  work,  must  appear  in  the 
employees'  column. 

55.  When  a  man  enters  the  employ  of  this  Board  the  inspector 
with  whom  he  first  serves  shall  make  note  of  it  at  the  time  on  his 
daily  report. 

56.  Each  inspector  will  designate  on  each  day's  report  and 
time  card  the  exact  point  at  which  he  will  begin  work  on  the  next 
working  day  and  on  what  street  and  in  what  direction  he  will 
move ;  also  the  exact  hour  and  place  of  roll-call  and  the  place 
designated  for  roll-call  the  following  morning. 

57.  Whenever  a  marked  tree  is  cut  the  inspector  in  charge 
shall  incorporate  the  fact  (giving  marks)  in  his  daily  report. 

58.  Inspectors  will  report  as  trees  all  young  growth  above 
three  inches  in  diameter. 

59.  When  brush  is  cut  and  ground  burned  over  inspectors  will 
report  in  square  yards  the  area  cleared  daily. 

60.  If  men  are  sent  away  on  special  duty  by  an  inspector  he 
must  state  the  reason  on  his  report  and  mark  time  card  "  see 
report "  opposite  such  names. 

61.  Superintendents,  special  inspectors  and  all  other  assistants 
in  the  field  must  state  on  their  daily  reports  when  and  where  they 
meet  their  men;  and  inspectors  must  also  note  on  their  reports 
the  time  of  such  visits. 

Per  order  of  the  committee, 

E.  H.  FOEBUSH,  Director. 


APPENDIX.  xxvii 


APPENDIX    C. 


AN  EXTRACT  FHOM  A  DESCRIPTION  OF  SECTION  8,  MEDFORD, 
AS  IT  APPEARS  IN  THE  SECTION  BOOK,  SHOWING  THE 
CONDITION  OF  THAT  SECTION  AND  THE  WORK  DONE  IN 
IT  IN  1891.  [THIS  SECTION  INCLUDES  THE  GLENWOOD 
DISTRICT.] 

MEDFORD,  SECTION  8. 

Boundaries. 

Commencing  at  a  point  on  the  centre  line  of  Main  Street,  in 
front  of  the  Boston  &  Maine  station  of  the  Medford  branch  rail- 
road ;  thence  easterly  by  the  centre  line  of  said  railroad  to  the 
centre  line  of  the  main  line  of  the  Boston  &  Maine  Railroad  ;  thence 
northerly  on  said  main  line  of  railroad  to  a  creek  flowing  under 
said  railroad  (the  centre  line  of  said  creek  being  the  boundary 
line  between  Medford  and  Everett)  ;  thence  northwesterly  and 
northerly  by  said  boundary  line  to  the  centre  line  of  Salem  Street 
to  Valley  Street ;  thence  westerly  by  said  Valley  Street  to  Forest 
Street ;  thence  southerly  by  the  centre  line  of  said  Forest  Street 
and  Main  Street  to  the  point  in  front  of  the  railroad  station,  the 
point  of  beginning. 

Description. 

Section  8,  Medford,  contains  the  cottage  formerly  occupied  by 
Mr.  L.  Trouvelot,  the  gentleman  who  imported  the  gypsy  moth 
and  accidentally  liberated  it  here.  The  southwestern  angle  of  the 
section  near  the  Medford  branch  railroad  station  constitutes  a 
large  part  of  the  business  portion  of  the  town.  It  is  quite  com- 
pactly built  up  with  dwelling-houses,  shops,  stores,  etc.  The 
traffic  with  outside  towns  is  considerable.  The  principal  thorough- 
fare, Salem  Street,  is  the  high-road  to  Maiden  and  the  towns  to 
the  east.  Forest  Street,  which  forms  the  western  boundary,  is 
much  used  for  carriage  driving.  On  the  Medford  branch  railroad 
and  within  this  section  are  the  Park  Street  and  Glenwood  stations. 
Near  these  stations  and  on  the  intervening  land  along  the  line  are 
the  homes  of  small  householders  and  people  whose  business  is  in 
Boston.  Here,  as  elsewhere  through  much  of  this  section,  each 
house  has  its  lot  of  land  and  generally  a  small  garden  or  orchard. 


xxviii  THE  GYPSY  MOTH. 

The  streets  are  usually  well  provided  with  shade  and  ornamental 
trees,  many  of  which  are  large  and  stately  elms.  In  the  spring  of 
1891,  when  work  was  first  begun  by  the  commission,  the  greater 
portion  of  this  plain,  including  the  swamp,  was  covered  with 
a  young  coppice  intermingled  with  bushes  and  undergrowth. 
Near  the  southern  border  of  this  tract  the  Anderson  Pressed 
Brick  Company  erected  extensive  works  in  1886  on  the  ground 
used  more  than  twenty  years  ago  by  Trouvelot  for  his  silk-worm 
pasture. 

Gravelly  creek  runs  through  the  western  part  of  the  section  near 
the  Forest  Street  boundary.  The  northern  boundary  of  the  sec- 
tion lies  close  to  the  rocky  ledge  which  marks  the  beginning  of  the 
Middlesex  Fells.  Near  the  centre  where  the  insect  was  first 
colonized  there  is  a  large  tract  of  woodland  suitable  for  the  shelter 
and  propagation  of  an  insect  pest.  Upon  the  west  several  streets 
much  travelled,  and  with  gardens  and  orchards  on  either  hand,  lead 
toward  the  centre  of  the  town.  On  the  south  is  a  railroad  which 
terminates  at  the  heart  of  the  infested  district  and  is  supported  by 
a  traffic  with  Boston.  The  principal  thoroughfare  connecting 
Medford  with  eastern  towns  runs  through  the  heart  of  the  section. 
Another  large  thoroughfare  marks  its  eastern  border,  and  a  stream 
which  flows  north  or  south  as  the  tides  rise  and  fall  rises  in  the 
section  and  flows  to  the  Mystic  River.  Here  we  have  all  the 
requisites  for  the  sustenance  of  the  insect  and  all  facilities  for  its 
transportation  in  all  directions. 

The  commission  appointed  by  Governor  Brackett  to  "  check  the 
spreading  and  secure  the  extermination  "  of  the  gypsy  moth  un- 
doubtedly destroyed  large  numbers  of  moths  in  this  section  by 
burning,  by  scraping  off  the  eggs  and  by  spraying ;  yet  when  the 
agents  of  the  Board  of  Agriculture  first  entered  the  section,  in 
March,  1891,  its  condition  was,  to  say  the  least,  alarming.  Some 
parts  of  the  brush  and  woodland  were  so  infested  with  the  eggs  of 
the  species  that  it  was  utterly  impossible  with  the  men  and  means 
at  our  command  to  destroy  them  by  hand.  There  were  acres  of 
ground  where  egg-clusters  were  numerous.  Many  eggs  were  laid 
on  the  ground  and  were  found  in  great  numbers  in  excavations 
where  people  had  dug  out  clay  or  sand.  A  stone  wall  which  was 
torn  down  (the  lower  surfaces  of  the  rocks  being  thereby  exposed) 
presented  a  remarkable  spectacle.  There  being  no  large  trees 
near  the  wall,  it  formed  a  refuge  and  concealment  for  the  moths 
that  fed  on  the  neighboring  bushes  and  saplings.  On  one  rock 
over  one  hundred  large  egg-clusters  were  counted.  "When  the 
number  of  eggs  contained  in  a  single  egg-cluster  is  considered,  it 
is  apparent  that  millions  of  caterpillars  would  have  hatched  in 


APPENDIX.  xxix 

this  wall  had  the  eggs  not  been  destroyed.  The  trunks  of  some 
of  the  trees  were  actually  yellow  with  egg-clusters.  Though  the 
insects  were  not  distributed  equally  over  the  entire  section,  there 
were  many  places  where  eggs  were  found  in  sufficient  numbers  to 
have  let  loose  a  destroying  host  upon  the  entire  neighborhood.  A 
large  per  cent,  of  the  yards  within  one-half  mile  of  the  Trouvelot 
house  were  thus  infested. 

The  yard  of  the  Anderson  Pressed  Brick  Company  includes  a 
part  of  the  wooded  section  hereinbefore  described.  At  the  present 
time  the  eastern  portion  of  the  yard  is  covered  with  a  scattered 
growth  of  young  oaks  and  bushes.  Near  the  buildings  and 
attached  to  them  on  the  east  are  several  sheds  in  which  are  piled 
many  thousands  of  the- finest  quality  of  pressed  brick.  East  of 
these  are  several  detached  sheds  also  filled  with  brick.  Near 
them  is  a  pile  of  broken  bricks  about  thirty  yards  in  length, 
fifteen  feet  in  width  and  ten  feet  in  height.  These  sheds  and  the 
brick-bat  pile  are  among  the  oaks,  the  pile  being  heaped  against 
some  of  the  trees.  "When  the  work  in  the  brick  yards  was  begun 
by  the  commission  on  March  21,  1891,  the  entire  premises  were 
infested  by  the  gypsy  moth.  About  three  hundred  thousand 
bricks  were  stacked  in  the  sheds  and  two  hundred  thousand  out- 
doors under  the  trees.  The  crevices  between  these  bricks  gave 
opportunity  for  the  moths  to  deposit  their  eggs.  The  bricks 
under  the  sheds  near  the  buildings  had  not  been  much  frequented 
by  the  moth,  but  three-fifths  of  those  under  the  trees  were  more  or 
less  covered  with  eggs.  The  egg-clusters  were  found  on  the 
ground  and  under  the  floors,  on  the  sides  and  under  the  roofs  of 
the  sheds,  under  the  stumps  and  about  the  roots  of  trees,  on  their 
trunks  and  limbs  and  in  almost  every  conceivable  sheltered  place. 
As  the  infested  bricks  were  likely  to  be  transported  in  all  direc- 
tions, the  danger  of  the  distribution  of  the  moth  by  this  means 
appeared  great.  A  capable  man  was  at  once  stationed  in  the  yard 
to  examine  all  bricks  sent  out.  The  finest  quality  of  bricks  sent 
out  previous  to  this  time  had  been  shipped  to  a  distance.-  Most 
of  them  were  used  for  fireplaces  and  were  cleaned  by  the  brick 
company  before  shipment,  and  in  this  way  all  eggs  were  probably 
taken  off.  Many  localities  to  which  bricks  had  been  shipped  were 
afterwards  examined.  The  work  in  this  yard  was  pushed  with 
the  greatest  energy.  Two  hundred  and  thirty-two  thousand  one 
hundred  and  ninety-five  bricks  were  examined,  and  all  those 
infested  were  cleaned  and  the  eggs  burned.  The  shed  most  badly 
infested  was  burned.  The  floors,  roofs,  etc.,  of  the  others  were 
torn  up  wherever  necessary,  and  the  eggs  taken  from  them. 
Some  of  the  trees  near  the  shed  were  cut  down  and  burned.  The 


xxx  THE   GYPSY  MOTH. 

brick-bat  pile  was  surrounded  by  a  board  fence  eighteen  inches 
high.  This  was  covered  with  tarred  paper,  and  before  the  cater- 
pillars began  to  hatch  in  the  pile  the  paper  was  covered  with  a 
mixture  of  pine  tar,  printers'  ink  and  crude  petroleum.  This 
fence  the  young  caterpillars  were  unable  to  scale.  The  trees  in 
the  brick  yard  were  inspected  and  the  eggs  on  them  destroyed. 
Fire  was  run  through  the  underbrush,  but  this  did  not  kill  all  the 
eggs.  One  section  of  the  yard  was  burned  experimentally  by 
spraying  the  ground  with  crude  petroleum  after  the  brush  had 
been  set  on  fire.  On  this  section  no  signs  of  the  caterpillars 
were  seen  during  the  year.  In  other  sections,  where  some  eggs 
survived  the  burning  and  hatched,  all  vegetation  was  sprayed 
with  Paris  green  several  times  during  the  season.  At  the  end  of 
the  season  it  was  difficult  to  find  any  sign  of  the  moth  in  the  yard. 
Trees  and  bushes  were  cut  down  over  a  tract  of  one  hundred  acres, 
and  fire  was  run  over  it.  Any  spot  that  escaped  the  fire  was 
thoroughly  burned  by  the  use  of  crude  petroleum. 

The  inspection  of  the  towns  on  the  border  line  of  the  infested 
district  occupied  so  much  time  in  the  spring  of  1891  that  it  was 
found  necessary  to  neglect  until  egg-hatching  time  a  large  tract 
near  the  centre  of  the  district  in  Maiden  and  Medford.  Time  was 
found,  however,  to  inspect  the  large  trees  along  the  highways  and 
railroads.  The  eggs  found  on  them  were  destroyed  and  the  trees 
were  banded  with  tarred  paper,  which  was  kept  covered  with  the 
mixture  used  in  the  brick  yard.  This  prevented  the  larvae  from 
ascending  these  trees,  and  reduced  the  danger  of  their  being 
carried  out  of  the  district.  Most  of  the  trees  in  the  section  were 
sprayed  two  or  three  times  during  the  season  with  a  mixture  con- 
taining Paris  green,  in  some  places  where  badly  infested  they  were 
sprayed  four  times ;  nearly  all  vegetation,  in  fact,  was  sprayed. 
Holes  in  the  tree  trunks  which  offered  hiding-places  for  the  larvae 
were  filled  with  cement.  Burlap  bands  were  put  about  the  trees 
after  the  caterpillars  began  to  cluster,  and  by  these  means  the  vast 
increase  was  kept  down. 

As  soon  as  the  female  moths  had  laid  their  eggs  and  died,  a 
small  force  of  men  began  destroying  the  eggs.  It  was  soon 
noticeable  that,  while  vast  numbers  of  last  season's  egg-clusters 
which  had  hatched  were  found,  very  few  newly  laid  clusters  ap- 
peared. Every  nook  and  crevice  was  searched  with  the  greatest 
care  to  discover  and  destroy  all  traces  of.  the  moth.  While  the 
leaves  remained  on  the  trees,  buildings,  fences,  woodpiles  and  all 
hiding-places  near  the  ground  were  searched.  As  the  leaves  fell 
the  trees  were  examined  and  cleaned  of  eggs.  Where  the  trees 
were  thickly  infested  the  leaves  were  raked  up  and  burned ;  thus 


APPENDIX. 

every  possible  effort  was  made  to  exterminate  the  moth  by  gather- 
ing the  eggs. 

After  going  over  the  entire  section  carefully,  an  estimate  of  the 
number  of  eggs  found  was  made.  Comparing  this  with  the 
estimated  number  found  in  the  spring,  it  was  seen  that  the  number 
found  in  the  fall  was  about  twenty  per  cent,  of  the  number  found 
in  the  spring.  The  data  for  this  estimate  were  very  complete,  and 
were  taken  from  the  daily  reports  of  the  inspectors. 


xxxii  THE  GYPSY  MOTH. 


APPENDIX    D. 


REPORTS  OF   ENTOMOLOGISTS  WHO  VISITED  THE   INFESTED 
REGION  IN  1893. 

REPOKT  OF  DR.  A.  S.  PACKARD  OF  BROWN  UNIVERSITY,  LATE  OF 
THE  UNITED  STATES  ENTOMOLOGICAL  COMMISSION. 

PROVIDENCE,  R.  I.,  June  19,  1893. 
Prof.  C.  H.  FERNALD. 

MY  DEAR  SIR  :  —  Having  been  asked  to  give  my  impressions 
of  the  work  now  being  done  at  Maiden  and  vicinity  in  exterminat- 
ing the  gypsy  moth,  I  will  say  that  it  made  a  good  impression  on 
me,  and  I  have  no  adverse  criticisms  to  make.  Mr.  Forbush  seems 
exactly  adapted  for  the  work  intrusted  to  him.  I  was  struck 
with  the  ability  shown  in  organizing  and  systematizing  the  whole 
work,  and  the  readiness  and  interest  shown  by  the  men  under  Mr. 
Forbush.  The  office  and  its  system,  the  storehouse  and  its  appa- 
ratus, interested  me  very  much,  and  the  new  and  ingenious  devices 
for  spraying  and  in  other  ways  destroying  the  eggs  and  worms. 
It  seems  to  me  the  work  is  practical  and  thorough  throughout, 
and  must  bear  good  fruit  this  season. 

In  the  short  time  I  spent  I  saw  nothing  to  find  fault  with,  but 
much  to  commend.  I  say  this  without  wishing  to  merely  say 
something  pleasant,  but  because  I  mean  it. 

Yours  very  truly, 

A.  S.  PACKARD. 


REPORT    OF    DR.  J.  A.  LINTNER,  STATE  ENTOMOLOGIST  OF  NEW 
YORK. 

OFFICE  OF  STATE  ENTOMOLOGIST,  ROOM  27,  CAFIT»L, 

ALBANY,  June  22,  1893. 
Prof.  C.  H.  FERNALD. 

MY  DEAR  SIR  :  —  The  two  days  that  I  passed  last  week,  in 
compliance  with  the  request  of  the  gypsy  moth  committee  of  the 
State  Board  of  Agriculture  and  of  yourself,  in  inspecting  the  oper- 
ations of  the  committee  through  its  director,  Mr.  E.  H.  Forbush, 
were  highly  gratifying  and  satisfactory  to  me.  I  wa»  not  pre- 


APPENDIX.  xxxiii 

pared  to  see  that  such  progress  had  been  made  toward  the  exter- 
mination of  the  notorious  gypsy  moth.  It  was  a  surprise  to  me 
that  in  the  brief  space  of  three  years  the  fearful  ravages  of  the 
insect  as  described  to  me  and  as  pictured  in  photographs  could 
have  been  reduced  to  such  a  comparative  harmlessness  that  to  the 
ordinary  observer  no  indication  of  its  presence  was  visible,  and 
that  in  a  ride  of  an  entire  day  through  several  of  the  "  infested 
towns,"  including  a  visit  to  localities  which  had  been  frightfully 
scourged,  not  a  single  example  of  the  caterpillar  was  found  by 
me,  although  diligent  search  for  it  was  made. 

How  a  work  of  such  magnitude,  extending  over  so  large  a  terri- 
tory, could  have  been  accomplished,  was  a  wonder  and  an  enigma 
to  me,  until  I  became  acquainted  with  the  means  by  which  it  had 
been  brought  about.  These  are,  in  part :  — 

First.  Your  work  at  the  insectary  is  largely  supplementing 
that  being  conducted  at 'the  Maiden  headquarters.  I  regard  it  so 
exceedingly  valuable  and  so  absolutely  essential  to  the  best  results 
in  field  work,  the  one  to  check  and  therefore  to  aid  the  other. 

Second.  The  committee,  I  am  confident,  have  been  both  wise 
and  fortunate  in  their  selection  of  Mr.  Forbush  as  director  of  field 
work.  I  think  that  I  estimate  correctly  when  I  say  that  he  is 
eminently  fitted  for  the  important  and  responsible  position.  A 
high  degree  of  judgment  and  discretion  has  evidently  been  exer- 
cised in  the  selection  of  those  employed  by  him  and  the  retention 
of  those  best  qualified  for  the  duties  assigned  them.  The  execu- 
tive ability  displayed  by  him  in  the  organization  of  his  force,  its 
direction,  guidance,  supervision,  equipment,  accountability,  etc., 
seems  to  me  remarkable,  and  to  go  far  toward  the  accounting  for 
the  singular  success  that  has  attended  his  administration. 

Third.  The  "  storehouse  "  greatly  interested  me.  It  may  prop- 
erly be  called  an  "  arsenal,"  for  it  is  furnished  with  all  the 
appliances  needed  for  conducting  in  the  most  effective  manner  the 
warfare  in  which  you  are  engaged.  In  it  are  found  not  only  all 
of  the  more  important  instruments  and  materials  that  economic 
entomology  had  tested  in  former  years  but  many  new  ones,  called 
into  use  for  the  first  time,  as  the  need  had  become  apparent  and 
the  ability  for  their  conception  and  production  was  at  command. 
With  such  means,  as  above  indicated,  your  State,  which  has 
been  liberal  in  its  appropriations,  has  a  right  to  expect  ample 
returns.  It  will  not  be  disappointed,  for  you  have  already  accom- 
plished more  than  could  have  been  reasonably  expected. 

I  trust  that  your  Legislature  will  see  the  wisdom  of  continuing 
the  work  under  suitable  appropriations,  until  the  extermination  of 
the  insect  has  been  attained,  or  at  least  until  it  shall  hare  been. 


xxxiv  THE  GYPSY  MOTH. 

reduced  to  entire  harmlessness,  and  in  position  never  again  to 
develop  in  injurious  numbers  or  to  invade  other  States. 

I  have  been  asked  to  offer  such  criticisms  or  suggestions  as  I 
might  deem  it  proper  to  make.  I  have  found  nothing  to  criticise, 
but,  on  the  contrary,  have  received  instruction  from  what  I  saw. 

Under  the  permission  given,  I  will  offer  two  suggestions  :  — 

1.  As  what  may  be  called  the  mechanical  details  of  field  work, 
as  burlapping,  liming,  spraying,  egg  collecting,  etc.,  are  steadily 
diminishing,  there  will  be  the  greater  need  (as  well  as  the  oppor- 
tunity) of  scientific  work,  to  round  up,  as  it  were,  the  labors  of 
the  committee,  to  aid  in  its  completion,  to  render  it  available  for 
future   use   wherever  the  necessity   may  arise  in  this  or  similar 
insect  invasions,  and  to  make  such  a  contribution  to  science  as 
Massachusetts  has  ever  been  ready  to  do  when  the  occasion  has 
offered. 

I  would,  therefore,  suggest  (and  recommend,  if  I  dare  venture 
to  do  so)  that  the  committee,  if  possible,  avail  themselves  of  more 
of  your  time  and  service.  Your  habits  of  thought,  observation 
and  study  seem  specially  fitted  to  the  work  that  you  are  now  con- 
ducting for  the  committee.  Further,  the  experience  that  you  have 
gained  is  of  so  great  value  that  it  should  not  be  lost  to  them.  I 
do  not,  however,  see  how  this  could  be  brought  about  under  your 
existing  relations  with  the  college  and  agricultural  station.  I  am 
sure  that  there  is  an  ample  field  for  your  entire  service.  If  the 
committee  could  offer  you  a  sufficient  inducement,  is  it  not  pos- 
sible that,  while  retaining  your  connection  with  the  college  and 
station,  you  could  be  released  from  the  discharge  of  the  duties, 
say  for  two  or  three  years,  and  devote  yourself  wholly  to  the 
gypsy  moth  ?  So  positive  am  I  of  the  utility  of  such  an  arrange- 
ment, that  I  sincerely  hope  that  it  may  be  accomplished. 

2.  Just  at  this  stage  of   the   committee's  work  I  would  sug- 
gest that  the  cultivation   of  the  parasites  of   the  gypsy  moth  be 
entered  upon  and  conducted  with  all  the  knowledge  and  skill  that 
can  be  brought  to  bear  upon  it.     Far  more  is  to  be  hoped  from 
this  than  from  the  costly  and  problematical  search  for  and  impor- 
tation of  its  European  insect  enemies.     Nearly  a  score  of  native 
parasites  are  already  known  to  prey  upon  it,  and  we  may  expect 
this  number  to  be  materially  increased.     Something  like  the  fol- 
lowing method  of  cultivation  might  be  pursued  :  — 

Collect  the  pupae  as  soon  as  they  are  to  be  found,  so  as  not  to 
give  opportunity  for  the  escape  of  the  earlier  maturing  parasites. 
None  should  be  destroyed,  but  carry  all  carefully  to  headquarters 
at  Maiden,  suitable  provisions  having  been  previously  made  for 
their  reception  and  care. 


APPENDIX.  xxxv 

If  80,000,  as  reported,  were  collected  last  year,  perhaps  from 
15,000  to  20,000  might  be  secured  this  year.  Arranged  in  a 
single  layer,  a  case  not  exceeding  twenty-five  square  feet  of  area 
would  be  ample  for  them,  and  leave  space  at  one  end  for  feeding 
larvae. 

By  means  of  cold  storage,  delay  the  development  and  emergence 
of  the  parasites  until  larvae  are  in  readiness  in  which  they  may 
oviposit. 

Egg-clusters  collected  this  season  shall  be  so  regulated  by 
temperature  that  they  will  give  out  their  larvae  as  soon  as  food  is 
obtainable  for  them. 

With  the  feeding  larvae  in  one  part  of  the  case  with  the  pupae,  they 
will  at  once  be  found  by  the  parasites  and  all  of  their  eggs  deposited 
in  them  if  the  larval  supply  is  proportioned  to  their  need. 

When  the  parasitism  is  finished,  the  larvae  may  be  fed  in  con- 
finement to  maturity,  if  practicable,  provided  that  conditions 
favorable  to  the  prevention  of  disease  or  other  fatality  can  be 
given  them  ;  or  they  may  be  transferred  to  isolated  trees  selected 
for  the  purpose,  where  they  may  complete  their  growth  and  be  pro- 
tected from  destruction  by  birds  by  inclosing  the  trees  in  netting. 
The  following  season  the  parasites,  unless  desired  to  extend  their 
multiplication  by  again  rearing  them  in  confinement,  may  be  per- 
mitted to  escape  and  seek  their  prey  abroad. 

The  parasitized  caterpillars  might  be  conveyed  to  the  localities 
where  the  parasites  are  the  most  needed. 

Gathering  the  parasites  from  the  case  after  their  death  would 
give  every  species  which  was  parasitic  on  the  larvae  and  pupae 
(except  such  as  may  have  emerged  from  the  larvae),  and  their 
proportionate  number,  from  which  the  most  efficient  could  be 
ascertained.  Examination  would  also  show  the  proportionate 
number  of  pupae  that  had  been  destroyed  by  parasites. 

The  above  plan  may  not  have  been  properly  digested  by  me, 
and  there  are  no  experiments  of  the  kind  to  serve  as  a  guide.  So 
far  as  I  know  it  has  not  been  attempted  on  a  large  scale  (the 
multiplication  of  icerya  parasites  in  California  was  somewhat 
similar) ,  but  if  done  with  the  knowledge  that  you  could  bring  to 
bear  upon  it,  I  am  sanguine  of  its  success.  Possibly  by  this 
means  only  can  the  desired  extermination  of  the  gypsy  moth  be 
attained. 

If,  under  the  existing  law,  the  carrying  of  the  living  insect 
from  one  town  to  another  is  prohibited,  amendment  for  the  above- 
named  purpose  could  no  doubt  be  secured. 

Very  truly  yours, 

J.    A.    LlNTNEB. 


xxxri  THE  GYPSY  MOTH. 


REPORT  OF  PROF.  JOHN  B.  SMITH,  D.Sc.,  OF  RUTGERS  COLLEGE, 
STATE  ENTOMOLOGIST  OF  NEW  JERSEY. 

NEW  BRUNSWICK,  N.  J.,  June  20, 1893. 

DEAR  Dr.  FERNALD  :  —  Since  my  return  to  New  Brunswick  I  have 
been  thinking  over  what  I  saw  of  the  work  of  the  gypsy  moth 
committee  near  Maiden,  Lynn  and  Swampscott,  and  with  the 
lapse  of  time  my  admiration  for  the  work  accomplished  has  in- 
creased rather  than  diminished.  When  I  received  your  invitation 
I  was,  I  think  I  can  truly  say,  free  from  actual  prejudice,  yet  with 
a  disposition  to  believe  that  the  work  of  the  committee  was 
palliative  merely,  and  that  actual  extermination  was  impossible,  an 
impression  to  which  I  had  given  public  expression.  I  am  pleased 
to  say  that  I  have  seen  ample  evidence  to  induce  a  change  of 
opinion,  and  my  belief  is  now  that  if  the  committee  is  as  well 
supported  as  it  deserves  to  be  it  will  accomplish  the  end  for  which 
it  was  created.  With  this  expression  of  my  present  belief,  you 
will  understand  that  my  suggestions  are  not  in  the  nature  of 
adverse  criticism. 

First,  concerning  the  experiments  in  progress  at  Amherst,  at 
the  present  time.  These  consist  of  a  test  of  the  action  of  certain 
insecticides  on  larvae  of  all  ages,  and  in  contemplation  are  experi- 
ments concerning  possible  parthenogenesis,  fixing  the  relative  time 
of  issuing  of  the  sexes  from  one  batch  of  eggs  and  the  effect  upon 
the  fertility  of  the  eggs  of  close  breeding, — that  is,  between 
males  and  females  bred  from  the  same  egg-mass. 

All  these  experiments  are  not  only  of  the  highest  scientific 
interest,  but  also  of  the  utmost  practical  importance. 

If  parthenogenesis  is  possible,  the  danger  of  spreading  the 
insects  by  carrying  off  single  specimens  is  vastly  increased,  and  the 
most  stringent  measures  to  prevent  such  distribution  are  justified. 
While  parthenogenesis  in  the  Lepidoptera  is  extremely  rare,  yet 
cases  have  been  recorded  in  the  same  natural  group  to  which  this 
insect  belongs,  and  the  inquiry  is  therefore  by  no  means  a  merely 
curious  one. 

Fixing  the  relative  time  of  the  emergence  of  the  sexes  of  the 
same  brood  is  of  very  great  importance,  for,  if  males  and  females 
issue  at  such  intervals  as  to  make  it  unlikely  that  they  can  pair, 
the  danger  from  the  distribution  of  even  several  larvse  from  the 
same  batch  of  eggs  is  materially  lessened. 

The  determination  of  the  effect  of  in-breeding  is  equally  im- 
portant, for  much  the  same  reason. 

Finally,  the  experiments  with  insecticides  are  of  peculiar  interest, 


APPENDIX.  xxxvii 

from  the  fact  that  the  caterpillars  seem  unusually  resistant  to  the 
action  of  arsenic  in  doses  fatal  to  most  of  the  insects  known  to  us. 

There  is  one  criticism  to  be  made  on  all  the  above  experiments : 
they  are  on  too  small  a  scale  to  render  the  results  altogether  convinc- 
ing and  they  are  made  in  the  wrong  place  at  Amherst  rather  than  at 
Maiden,  Lynn  or  elsewhere  in  the  infested  region.  The  extreme 
caution  necessary  to  prevent  the  escape  of  specimens  of  the  larvae 
prevents  the  practice  of  certain  lines  of  out-door  work,  the  results  of 
which  would  supplement  the  in-door  or  laboratory  experiments. 

I  would  therefore  suggest  that  the  experiments  now  carried  on 
at  Amherst  be  duplicated  or  transferred  to  some  point  within  the 
infested  district  where  material  is  more  abundant,  and  where  there 
is  no  danger  of  introducing  the  insect  into  new  localities. 

These  experiments  must  of  course  be  made  by  a  trained  ento- 
mologist, or  by  a  competent  man  under  detailed  instructions.  By 
all  odds  the  most  satisfactory  plan  would  be  to  have  you  carry  on 
the  experiments  yourself,  for  they  would  then  command  universal 
acceptance  and  would  be  generally  regarded  as  conclusive. 

The  result  of  the  insecticide  experiments  thus  far  is  so  unusual 
that  I  would  recommend  a  further  series  of  experiments  to  deter- 
mine exactly  what  becomes  of  the  arsenic  eaten  by  the  insects ; 
whether  it  is  absorbed  or  whether  it  is  excreted,  and  how  much 
arsenic  an  insect  will  contain  when  its  intestinal  canal  is  filled  with 
poisoned  food  and  excreta  therefrom.  This  could  be  done  by 
feeding  larvae  on  leaves  sprayed  with  a  maximum  amount  borne 
by  the  foliage  for  say  three  or  four  days,  and  then  substituting 
fresh  food  free  from  poison.  A  chemical  test  should  be  made 
thereafter  every  day  or  every  day  or  two,  to  ascertain  the  presence 
or  absence  of  arsenic  in  the  larvae.  Microscopic  examinations  of 
the  digestive  tract  of  poisoned  larvae  should  also  be  made,  and 
should  be  compared  with  that  of  healthy  larvae,  to  ascertain 
whether  any  lesion  were  caused  that  might  result  in  a  degenerated 
adult.  The  excreta  of  larvae  fed  upon  poisoned  food  should  also 
be  analyzed  to  determine  the  amount  disposed  of  in  this  way. 

This  is  of  course  suggestive  merely ;  but  in  my  opinion  the 
present  occasion  is  an  unusually  good  one  to  gather  a  mass  of 
facts  whose  importance  to  economic  entomology  it  would  be  dif- 
ficult to  estimate. 

If  I  had  reason  to  speak  in  approbation  of  the  line  of  experi- 
ments laid  out  by  yourself  at  Amherst,  I  found  very  much  more 
to  admire  in  the  infested  district,  in  the  actual  field  work  under 
the  direction  of  Mr.  Forbush.  The  mere  organization  of  the  force 
and  the  plan  of  the  work  is  excellent ;  as  to  the  results  of  the 
methods  adopted,  the  fact  that  in  the  entire  infested  district 


xxxviii  THE  GYPSY  MOTH. 

visited  by  me  —  Maiden,  Lynn  and  Swampscott —  only  a  single 
half -grown  larva  was  discovered  speaks  loudest. 

I  was  extremely  interested  in  the  office  organization,  in  which 
the  system  of  entering  and  classifying  reports  enables  the  director 
and  the  members  of  the  committee  to  determine  at  once  the  exact 
condition  of  affairs  in  any  district.  The  notes  of  observations 
made  by  inspectors  are  many  of  them  of  the  greatest  interest, 
and  merit  editing  by  an  entomologist  capable  of  recognizing  facts 
and  separating  them  from  inferences  made  by  the  observer. 

The  inspection  of  the  tool-house  was  a  revelation  in  the  variety 
of  apparatus  it  afforded,  all  of  it  adapted  to  the  special  end  in 
view.  The  practical  value  of  all  the  apparatus  is  obvious,  and 
while  for  an  orchard  the  spraying  outfits  might  be  considered 
clumsy  and  somewhat  wasteful,  yet  when  the  character  of  the 
work  is  considered  the  apparatus  designed  for  the  fruit  grower  is 
manifestly  insufficient.  A  most  commendable  feature  in  the  work 
has  been  seeking  out  means  of  taking  advantage  of  the  peculiarities 
of  the  insect's  habits,  which  is,  after  all,  the  most  philosophical 
way  of  accomplishing  the  work  in  hand. 

It  would  be  altogether  too  long  a  task  to  go  into  details  con- 
cerning the  outfit  of  insecticide  machinery,  and  I  need  only  say 
that  I  can  find  absolutely  nothing  to  suggest  in  the  way  of  improv- 
ing the  methods  of  work. 

The  force  under  the  direction  of  Mr.  Forbtish  has  accomplished 
wonders,  and  I  feel  now  that  there  is  very  good  reason  for  the  be- 
lief that  the  gypsy  moth  can  be  exterminated,  provided  the  means 
are  furnished  by  the  Legislature  of  Massachusetts  in  as  liberal  a 
spirit  at  least  as  past  appropriations  have  been  made. 

I  have  been  asked  to  give  an  opinion  on  the  feasibility  of  intro- 
ducing European  parasites  of  this  insect,  to  keep  it  in  check.  I 
feel  very  decidedly  that  this  would  be  money  wasted.  This  and 
its  ally,  the  Nonne,  are  frequently  destructive  in  Europe,  and  if 
its  parasites  do  not  succeed  in  mastering  it  there,  there  is  no  reason 
for  believing  that  they  can  do  better  here. 

Nature  never  works  for  the  extermination  of  any  of  its  creatures, 
and  if  parasites  ever  exterminated  their  hosts  the  parasites  them- 
selves would  be  exterminated  for  the  want  of  food.  A  balance  is  all 
that  nature  aims  for.  A  parasite  which  would  be  able  to  exterminate 
the  gypsy  moth  in  this  country  must  be  one  that  would  prey  on  this 
one  insect  only ;  and  even  then  it  is  very  problematical  whether 
the  result  would  be  very  satisfactory,  for  to  enable  the  parasites 
to  do  their  work,  artificial  means  of  destroying  the  larvae  would 
have  to  be  abandoned  for  fear  of  killing  the  parasites  as  well. 

I  am  very  strongly  of  the  opinion,  therefore,  that  nothing  can 
be  gained  by  an  attempted  introduction  of  parasites. 


APPENDIX.  xxxix 

The  oft-cited  case  of  Vedalia  destroying  the  cottony  cushion 
scale  in  California  can  have  no  application  to  this  case,  for  the 
circumstances  there  were  so  peculiar  that  they  can  rarely  be  dupli- 
cated, and  are  not  similar  here. 

I  am  asked  to  express  an  opinion  as  to  the  work  done  and  to  be 
done  by  the  committee.  I  can  only  repeat  what  I  have  already 
said,  —  the  work  done  by  the  committee  as  at  present  organized 
is  admirable,  and  I  am  unable  to  point  out  a  method  in  which  it 
could  be  improved. 

Both  the  entomologist  and  the  director  thoroughly  understand 
the  problem,  and  are  working  for  success, —  a  success  that  I  now 
think  they  will  attain. 

As  to  the  work  yet  to  be  done,  I  am  not  in  a  position  to  give  an 
opinion,  because  I  had  no  time  to  cover  the  entire  ground.  From 
what  I  could  see  at  Maiden,  Lynn  and  Swampscott,  I  believe  that 
for  at  least  two  years  more  a  full  force  of  men  should  be  em- 
ployed, using  the  methods  that  have  proved  so  successful  and 
working  from  the  outer  limits  toward  the  central  district. 

The  most  useful  men  should  in  all  cases  be  retained  from  year  to 
year,  for  they  will  be  worth  at  least  double  the  sum  any  new  man 
could  be  valued  at,  and  will  know  just  exactly  what  is  to  be  done 
in  all  cases  and  just  what  to  look  for.  After  a  few  years  the  force 
of  men  could  be  safely  reduced  to  the  inspectors  and  a  few  ordi- 
nary workmen,  whose  principal  business  would  be  a  continuous 
examination  of  the  once-infested  district,  prepared  to  destroy  any 
isolated  brood  that  may  have  escaped  ;  and  finally  this  force  could 
be  reduced  to  the  director  and  a  very  few  inspectors,  who,  with 
the  experience  gained,  could  easily  command  the  entire  region 
until  lapse  of  time  proved  the  insects  exterminated. 
Very  truly  yours, 

JOHN  B.  SMITH. 
Dr.  C.  H.  FEKNALD,  Entomologist,  Gypsy  Moth  Commission,  Amherst,  Mass, 


KEPORT  OF  PROF.  CLARENCE  M.  WEED,  D.Sc.,  OF  THE  NEW 
HAMPSHIRE  COLLEGE  OF  AGRICULTURE  AND  THE  MECHANIC 
ARTS,  ENTOMOLOGIST  OF  THE  AGRICULTURAL  EXPERIMENT 

STATION. 

HANOVER,  N.  H.,  June  16,  1893. 
To  the  Gypsy  Moth  Committee. 

GENTLEMEN:  —  In  response  to  the  invitation  extended  by  you 
through  Professor  Fernald,  I  recently  visited  the  various  depart- 
ments of  gypsy-moth  work,  and  beg  leave  to  inform  you  of  the 
impressions  thus  received. 


3d  THE  GYPSY  MOTH. 

I  first  inspected  the  work  in  progress  at  the  insectary  at  Am- 
herst,  and  found  that  a  series  of  experiments  with  remedies  was 
being  conducted  under  the  most  careful  conditions ;  in  fact,  I  have 
never  seen  a  series  of  similar  experiments  carried  on  in  so  large  a 
scale  in  so  thoroughly  scientific  a  manner.  They  ought  certainly 
to  furnish  reliable  results,  which  will  be  of  great  value  outside  of 
the  gypsy-moth  work. 

I  next  went  to  Maiden,  and  in  company  with  the  other  visitors, 
Professor  Fernald,  Mr.  Forbush  and  Mr.  Reid,  looked  over  the 
ground  carefully.  The  general  impression  received  was  very 
favorable  as  to  the  amount  and  methods  of  work.  The  results 
already  reached  seem  to  be  remarkable,  and  I  was  greatly  surprised 
at  the  scarcity  of  gypsy  caterpillars.  The  methods  of  fighting  the 
pest  have  evidently  been  developed  along  with  the  knowledge  con- 
cerning it,  and  are  well  adapted  to  the  end  in  view. 

The  only  suggestion  I  have  to  make  concerns  the  lack  of  ade- 
quate facilities  for  studying  the  life  history  of  the  pest  at  head- 
quarters. It  seems  to  me  that  if  a  room  adapted  to  the  purpose 
could  be  set  apart,  and  a  man  of  entomological  training  be  detailed 
to  make  out  the  biological  points  yet  in  doubt,  valuable  results  might 
be  reached.  I  should  suppose  that  it  would  hardly  be  necessary  to 
call  in  an  entomologist  of  note  if  Professor  Fernald  is  willing  to 
supervise  the  work  of  the  one  detailed  to  carry  on  such  observations 
and  experiments.  In  fact,  the  results  would  have  an  added  value 
if  carried  on  both  at  Maiden  and  Amherst  under  one  direction. 

I  was  especially  interested  to  learn  of  the  results  that  have  been 
reached  with  the  arsenate  of  lead.  Even  if  it  does  not  kill  gypsy 
caterpillars  as  quickly  as  does  Paris  green,  it  seems  probable  that 
it  will  make  a  valuable  insecticide  for  many  other  purposes. 

Thanking  you  for  the  opportunity  you  afforded,  and  assuring 
you  of  whatever  support  I  may  be  able  to  render,  I  am, 
Yours  respectfully, 

CLARENCE  M.  WBBD. 


REPORT  OF   DR.  H.  T.  FERNALD,  OP  THE   PENNSTLTANIA   STATE 

COLLEGE. 

STATE  COLLEGE,  CENTRE  COUNTY,  PA.,  June  19,  1893. 
To  the  Gypsy  Moth  Commission. 

GENTLEMEN  :  —  In  accordance  with  your  request,  extended  to 
me  by  Prof.  C.  H.  Fernald,  I  have  examined  the  work  in  progress 
at  Maiden  and  Amherst,  and  ana  both  interested  aad  pleased  with 
what  I  have  seen. 


APPENDIX.  xli 

Previous  to  my  visit  to  Maiden  I  felt  some  doubt  as  to  whether 
it  was  possible  to  exterminate  the  gypsy  moth,  as  I  had  had 
some  previous  knowledge  of  it  and  of  its  ravages  in  Massa- 
chusetts, being  at  Amherst  when  it  was  first  reported  to  the  ex- 
periment station  there  in  1889,  and  having  carefully  looked  over 
the  matter  at  that  time.  Since  my  visit  a  careful  considera- 
tion of  the  methods  used  and  of  the  results  already  obtained 
has  convinced  me  that  extermination  is  not  only  probable,  but 
certain,  if  the  work  be  prosecuted  for  a  sufficient  length  of 
time. 

On  one  or  two  points  I  have  gathered  impressions  which  may 
perhaps  be  worthy  of  mention  here  :  — 

1 .  I  think  that  the  position  so  far  held  by  the  committee  with 
reference  to  the  effect  of  parasites  is  a  wise  one.     I  have  never 
heard  of  a  case  where  an  insect  was  exterminated  by  its  parasites, 
the  relation  of  the  two  forms  at  any  one  time  being,  in  numbers, 
very  close.     A  reduction  in  the  numbers  of  the  host  is  always 
followed  by  a  similar  reduction  in  the  numbers  of  the  parasites, 
leaving  to  those  individuals  of  the  host  which  have  escaped  an 
opportunity  for  rapid  and  unchecked  increase  until  overtaken  by 
a  corresponding  but  later  increase  in  numbers  of  the  parasites. 
For  this  reason  parasites  cannot  be  relied  upon  to  do  the  work 
needed  in  the  case  of  the  gypsy  moth. 

2.  The  method  of  burning  over  infested  areas  in  connection 
with  burlapping  the  trees  seems  to  me  to  be  a  most  effective 
method  of  procedure  if  the  precaution  of  burning  for  a  sufficiently 
great  distance  beyond  the  limits  of  the  infested  area  be  carefully 
observed.     My  impression  is  that  the  edge  of  the  burned  area 
should  always  be  at  least  two  hundred  feet  outside  these  limits, 
as  far  as  these  can  be  ascertained. 

The  work  so  far  accomplished  shows  on  its  face  that  the 
methods  in  use  are  the  result  of  experience,  and  that  they  are 
most  efficacious. 

It  seems  to  me  that  two  things  are  greatly  to  be  feared :  — 

1.  That  the  time  is  near  when  searches  with  negative  results 
may  tend  to  produce  carelessness  on  the  part  of  the  searchers. 

2.  That  the  apparent  disappearance  of  the  moths  may  lead 
the  Legislature  into  the  error  of  abolishing  the  committee  at  the 
time  when  its  work  will  show  the  fewest  results,  but  will  in  reality 
be  the  most  valuable,  —  in  fact,  would  be  absolutely  necessary  to 
insure  the  prevention  of  some  future  invasion. 

The  work  done  by  the  committee  in  the  way  of  testing  insecti- 
cides in  the  field  at  Maiden  and  in  the  laboratory  at  Amherst  is 
of  great  value,  and  the  importance  of  learning  with  the  greatest 


xlii  THE  GYPSY  MOTH. 

accuracy  just  how  successful  each  method  is,  cannot  be  overesti- 
mated. The  care  with  which  the  experiments  at  Amherst  are 
conducted  guarantees  the  accomplishment  of  this  most  important 
task,  while  the  discovery  of  a  new  insecticide  with  the  properties 
which  the  arsenate  of  lead  apparently  possesses  must  certainly  be 
worth  more  to  the  State  than  all  the  money  it  has  spent  for  the 
extermination  of  the  gypsy  moth. 

Yours  respectfully, 

H.  T.  FERNALD. 


APPENDIX.  xliii 


APPENDIX    E. 


REPORTS  OF  ENTOMOLOGISTS  WHO  VISITED  THE  INFESTED 
REGION  IN  1894.  —  OPINION  OF  THE  UNITED  STATES  EN- 
TOMOLOGIST. 

REPORT  OF  DR.  GEORGE  H.  PERKINS  OF  THE  UNIVERSITY  OF  VER- 
MONT, ENTOMOLOGIST  OF  THE  VERMONT  STATE  AGRICULTURAL 
EXPERIMENT  STATION. 

BUHLINGTON,  VT.,  July  10,  1894. 
Prof.  C.  H.  FERNALD. 

DEAR  SIR:  —  In  accordance  with  your  invitation  to  visit  the 
region  infested  by  the  gypsy  moth,  I  went  to  Maiden,  as  you  are 
aware,  and  through  the  very  cordial  assistance  of  both  yourself 
and  Mr.  Ware,  assistant  director,  was  enabled  to  see  in  a  most 
complete  and  satisfactory  manner  the  appliances  used  and  the 
various  methods  of  using  them. 

I  wish  to  express  my  appreciation  of  the  thorough  and  careful 
manner  in  which  the  work  was  being  done,  and  the  evident  desire 
of  those  engaged  in  it  to  execute  the  trust  committed  to  them  as 
faithfully  and  economically  as  possible.  No  work  of  the  sort 
which  I  have  ever  seen  or  heard  of  has  impressed  me  as  favorably 
as  did  that  of  the  officials  engaged  in  the  work  of  exterminating 
the  gypsy  moth. 

The  whole  nation  should  be  grateful  to  the  committee  for  what 
it  has  already  accomplished ;  for  it  is  my  belief  that,  had  not  the 
work  been  so  well  done  in  Massachusetts,  the  insect  would  ere  this 
have  spread  beyond  the  borders  of  that  State  and  now  threaten 
the  whole  land.  It  is  most  gratifying  to  find,  instead  of  this,  that 
the  ravages  of  the  moth  have  been  very  much  reduced  by  the 
efforts  of  the  committee. 

No  one  interested  in  economic  entomology  can  investigate  the 
work  in  office  and  field  without  at  once  discovering  that  a  vast 
amount  of  very  useful  information  has  been  gathered  which  should 
not  on  any  account  be  lost  to  science.  On  this  account  it  is  very 
greatly  to  be  desired  that  as  full  and  complete  a  report  as  possible 


xliv  THE   GYPSY  MOTH. 

of  the  work  of  the  committee  be  published,  for  much  that  such  a 
report  would  contain  would  necessarily  be  of  general  and  permanent 
value. 

The  question  has  been  asked,  Is  it  possible  to  exterminate  an 
insect  which  has  become  so  abundant  as  the  gypsy  moth  ?  Before 
I  visited  the  infested  region,  and  saw  what  had  already  been  done, 
I  was  quite  doubtful  as  to  the  expediency  or  the  possibility  of 
extermination ;  but  after  investigation  I  thought  differently.  It 
seems  to  me  very  clearly  the  wisest  and  most  economical  course, 
for  the  present  at  any  rate,  to  continue  the  work  as  it  is  now  going 
forward,  and  aim  at  extermination.  The  men  and  the  methods 
now  employed  are  so  successful  that  it  would  be  unwise  to  discon- 
tinue them  for  several  seasons  to  come. 

It  also  seems  to  me  that  the  functions  of  the  committee  might 
be  very  advantageously  extended,  so  that  in  their  discretion  they 
could  direct  their  destructive  agencies  against  such  other  insects  as 
might  be  easily  taken  in  hand. 

When  passing  through  some  of  the  towns  infested  by  the  gypsy 
moth  we  noticed  many  trees  the  foliage  of  which  had  been  wholly 
destroyed  by  the  canker-worm;  and  many  of  these  trees  could 
have  been  spra}Ted  by  those  engaged  in  spraying  neighboring  trees 
for  the  moth  at  small  cost  of  time  or  money. 

It  was  very  evident  that  private  enterprise  could  not  be 
depended  upon  to  deal  with  these  pests.  It  is  my  own  conviction 
that  the  most  efficient  and  the  cheapest  method  of  dealing  with 
any  insect  which  has  become  numerous  and  destructive  is  that 
adopted  in  the  case  of  the  gypsy  moth,  not  leaving  to  private  citi- 
zens the  too  great  task,  and  thus  ensuring  failure,  but  bringing 
the  authority  and  the  resources  of  the  State  to  the  work,  and 
carrying  it  forward  to  success. 

Is  it  not  probable  that,  had  the  gypsy  moth  not  been  stayed  in 
its  destruction,  the  loss  to  property  through  the  destruction  of 
shade  and  fruit  trees  would  have  been  more  than  the  cost  of 
extermination  has  thus  far  been? 

It  is  to  be  hoped  that  the  work  so  well  done  thus  far  will  not 
now  be  suffered  to  lag  through  lack  of  either  funds  or  popular 
support.  There  is  every  reason  for  continuing  it,  while  to  stop  or 
reduce  it  would  be  a  great  calamity. 

I  have  not  been  asked  to  praise  the  work  of  the  committee,  but 

rather  to  suggest  improvements  in  their  methods,  and  to  criticise 

whatever  I  might  find  deserving  it.     I  have  no  criticism  to  offer, 

nor  am  I  able  to  make  suggestions  other  than  those  given  above. 

I  am,  sir,  very  truly  yours, 

GEO.  H.  PERKINS. 


APPENDIX.  xlv 


REF©*T  OF  PROF.  F.  L.  HARVET  OF  THE  MAINE  STATE  COL- 
LEGE, BOTANIST  AND  ENTOMOLOGIST  OF  THE  MAINE  EXPERI- 
MENT STATION,  ORONO,  ME. 

To  the  Members  of  the  Gypsy  Moth  Committee  of  the  State  Board  of 
Agriculture  of  Massachusetts. 

GENTLEMEN  :  —  In  compliance  with  your  courteous  invitation 
(extended  to  me  through  Prof.  C.  H.  Fernald)  "to  inspect  the 
work  of  the  gypsy  moth  committee  and  give  my  impressions  and 
advice,"  I  visited  Maiden  the  latter  part  of  July,  and  spent  two 
days  examining  the  work  of  the  committee  in  the  office,  labora- 
tories and  field.  Through  the  courtesies  of  Director  E.  H.  For- 
bush  and  others  of  the  department  every  opportunity  was  afforded 
me  to  gain  a  thorough  knowledge  of  the  scope  and  character  of 
the  work  of  the  committee. 

I  went  to  Maiden  with  an  entirely  inadequate  conception  of  the 
territory  affected,  and  the  stupendous  undertaking  of  the  com- 
mittee to  reduce  or  exterminate  the  gypsy  moth.  I  first  visited 
the  office,  and  was  surprised  by  the  ingenuity  and  thoroughness 
displayed  in  keeping  the  field  notes  and  indexing  them  for  readv 
reference.  A  mass  of  information  regarding  the  habits,  natural 
history  and  anatomy  of  this  insect  has  been  accumulated  by 
Professor  Fernald,  Director  Forbush  and  their  assistants.  This 
seems  so  important  that  for  the  good  of  entomological  science  it  is 
hoped  it  may  be  sifted  by  a  competent  entomologist  and  published 
as  a  monograph  by  the  committee.  The  pains  taken  in  examining 
the  men  for  field  work  and  the  almost  military  exactness  required 
of  them  in  their  labor  and  reports  reflect  great  credit  upon  the 
organizing  ability  of  the  director,  and  speak  much  for  the 
efficiency  of  the  service. 

The  work  being  done  in  the  laboratory  and  insectary  upon  the 
life-history  of  the  moth,  its  parasites  and  histology,  and  upon 
remedies,  was  timely  and  thorough.  I  was  especially  interested 
in  the  histological  work,  conducted  by  Mr.  A.  H.  Kirkland,  to 
determine  if  possible  what  becomes  of  the  arsenical  poison  the 
full-grown  larvae  are  known  to  eat  with  impunity,  and  also  the 
trap  experiments  under  the  direction  of  Mr.  Kirkland. 

The  storehouse  for  apparatus  and  supplies  impresses  one  with 
the  magnitude  of  the  work,  and  is  instructive  in  the  novel 
apparatus  invented  to  fight  this  pest. 

The  results  obtained  in  the  experiments  on  insecticides,  by  Mr. 
F.  C.  Moulton,  are  most  important,  and  bid  fair  to  be  of  great 
usefulness  to  economic  entomology. 


xlvi  THE   GYPSY  MOTH. 

The  field  methods  of  searching  for  the  eggs,  larvae  and  pupse, 
the  burlapping  of  the  trees  and  the  careful  burning  of  infested 
areas  was  thorough  and  practical. 

Upon  the  whole,  the  methods  which  have  been  born  of  experi- 
ence and  adopted  by  the  committee  for  coping  with  the  pest 
impressed  me  as  ingenious  and  effective.  I  have  no  criticisms  to 
offer  upon  the  work  of  the  committee,  and  regard  the  results 
obtained  as  marvellous. 

Entomologists  are  generally  agreed  that  it  is  impossible  to 
exterminate  an  insect  by  means  of  its  parasites,  so  all  that  can  be 
hoped  for  in  this  direction  is  uncertain  aid  in  holding  it  in  check. 
Whether  it  is  possible  to  exterminate  an  insect  by  persistent  and 
thorough  hand-picking,  use  of  insecticides  and  fire  is  problematical, 
because  it  has  never  been  tried.  It  is  a  plausible  problem,  which 
we  hope,  for  the  good  of  economic  entomology,  the  gypsy  moth 
committee  may  have  the  opportunity  to  settle.  By  the  efficient 
work  of  the  committee,  in  three  years'  time,  this  insect,  which  was 
legion  and  doing  great  damage  over  a  wide  area,  has  been  reduced 
beyond  detection  by  common  observation.  We  spent  a  whole  day 
in  the  field,  and,  though  constantly  on  the  alert  for  specimens, 
saw  only  four  male  moths  and  no  larvae,  pupae  or  eggs.  So  thor- 
oughly has  the  work  been  done  that  intelligent  people  in  the  dis- 
trict wrongly  regard  the  work  of  the  committee  accomplished.  It 
is  the  scattering  colonies,  the  last  one  per  cent.,  that  will  demand 
more  thorough  work  than  the  other  ninety-nine  per  cent.,  and  your 
Legislature  and  citizens  will  need  to  be  thoroughly  impressed  with 
this  fact. 

Two  policies  present  themselves :  first,  whether  an  attempt  be 
made  to  fight  the  moth  to  the  finish ;  second,  whether  an  attempt 
be  made  to  merely  keep  it  in  check,  and  prevent  an  increase  to 
harmful  numbers. 

The  gratifying  work  of  the  committee  so  far  would  suggest 
continuance  in  the  good  work,  with  the  idea  of  extermination. 
This  would  absolutely  require  the  employment  of  a  force  of  men 
large  enough  to  keep  the  whole  infested  area  under  constant  sur- 
veillance for  some  time.  The  present  number  of  men  employed 
seems  to  me  to  be  inadequate,  as  large  areas  in  the  infested  dis- 
trict have  to  be  neglected  while  inspection  is  going  on  in  others. 
Unless  a  large  force  can  be  kept  constantly  employed  for  some 
years,  the  idea  of  extermination  will  have  to  be  abandoned  by  the 
committee. 

If  the  second  policy  be  adopted,  then  the  work  of  the  commit- 
tee for  the  present  is  practically  done.  Yet  a  permanent  force 
would  be  needed  to  keep  the  area  under  occasional  surveillances 


APPENDIX.  xlvii 

and  its  energies  directed  to  checking  local  outbreaks.  This  would 
be  an  interminable  job,  constantly  menaced  with  the  danger  of 
the  pest  spreading  over  large  areas  to  adjoining  States,  until  so 
widely  disseminated  as  to  be  beyond  human  power  to  control.  It 
would  seem  to  me  to  be  wiser  to. attempt  the  extermination  of  the 
pest  while  in  its  greatly  reduced  numbers  by  the  adoption  of  a 
liberal  financial  policy,  than  to  drop  the  work  and  in  a  decade  or 
sooner  have  it  to  do  all  over  again. 

We  regret  to  learn  (unofficially)  that  naturalists  are  breeding 
this  pest  for  purposes  of  study  outside  of  the  Commonwealth  of 
Massachusetts,  in  defiance  of  the  strict  laws  regarding  its  dissem- 
ination. 

I  heard  the  committee  criticised  by  citizens  and  others  because 
they  would  not  destroy  other  injurious  insects  besides  the  gypsy 
moth  in  the  infested  district.  We  understand  this  criticism  to  be 
unjust,  as  the  Legislature  confined  the  duties  of  the  committee 
strictly  to  the  suppression  of  this  one  insect,  and  to  use  the  money 
to  destroy  the  others  would  be  a  perversion  of  funds. 

That  it  would  be  a  wise  policy  for  every  State  to  have  an  en- 
tomological commission,  with  duties  as  broad  as  the  requirements 
of  economic  entomology,  we  have  no  doubt.  The  fact  that  the 
gypsy  moth  committee  has  paid  strict  attention  to  business  is  the 
reason  why  they  have  in  such  a  short  time  accomplished  so  much. 

In  closing,  I  desire  to  thank  the  committee  for  the  opportunity 
offered  me  to  study  the  life-history  of  this  insect,  and  to  become 
familiar  with  the  ingenious  and  effective  methods  used  in  coping 
with  it.  I  hope  the  committee  will  receive  the  financial  support 
from  the  Legislature  that  will  enable  it  to  succeed  in  this  stupen- 
dous undertaking,  which  does  not  alone  interest  Massachusetts 
but  also  the  adjoining  States  and  the  whole  country. 
Respectfully  submitted, 

F.  L.  HARVEY. 


REPORT   OF  PROF.  JOHN  H.  COMSTOCK  OF  CORNELL  UNIVERSITY, 
LATE   UNITED   STATES  ENTOMOLOGIST. 

ITHACA,  N.  Y.,  July  17,  1894. 

Mr.  WILLIAM  R.  SESSIONS,  Secretary  of  the   Committee  on  the  Exter- 
mination of  the  Gypsy  Moth  of  the  State  Board  of  Agriculture. 
SIR  :  —  In  compliance  with  the  request  of  your  committee,  trans- 
mitted to  me  through  Professor   Fernald,  I   visited   the   region 
infested  by  the  gypsy  moth,  and  spent  several  days  studying  what 
is  being  done  towards  the  extermination  of  this  species.     During 


xlviii  THE   GYPSY  MOTH. 

the  greater  part  of  this  time  I  was  accompanied  by  Professor 
Fernald  and  Mr.  E.  H.  Forbush,  who  explained  to  me  very  fully 
the  details  of  the  work. 

I  was  filled  with  admiration  of  the  work  that  is  being  done  by 
these  gentlemen,  and,  although  I  have  given  the  matter  very  care- 
ful thought,  I  am  unable  to  suggest  any  changes  in  their  methods. 
It  seems  to  me  that  the  methods  they  are  following  are  the  best 
possible,  so  long  as  the  object  of  the  work  is  the  extermination  of 
this  insect. 

But,  after  going  over  the  infested  region,  I  have  come  to 
have  grave  doubts  as  to  the  advisability  of  attempting  to  exter- 
minate this  pest.  I  am  not  prepared  to  say  that  I  consider  exter- 
mination impossible,  but  it  seems  to  me  that  the  attainment  of  this 
desired  end  is  highly  improbable.  It  is  true  there  are  certain 
peculiarities  in  the  habits  of  this  insect  that  give  hopes  of  the 
possibility  of  extermination.  Thus  the  slowness  with  which  the 
species  spreads  naturally,  owing  to  the  fact  that  the  female  does 
not  fly,  and  the  fact  that  the  larva  in  its  later  stages  descends  from 
the  trees  and  hides  during  the  day-time,  rendering  it  possible  to 
trap  it,  greatly  facilitate  the  work  of  destruction.  On  the  other 
hand,  the  wide  range  of  food  plants,  the  extent  of  the  area  in- 
fested, including  as  it  does  large  forests,  and  the  ease  with  which 
the  species  may  be  artificially  spread  by  means  of  vehicles,  all 
combine  to  make  the  task  a  very  great  one.  Still,  if  you  could  be 
provided  with  sufficient  funds  extending  over  a  sufficiently  long 
period,  I  believe  these  difficulties  could  be  overcome. 

But  I  feel  that  this  is  too  much  to  hope.  If  at  this  time,  so 
soon  after  the  terrible  ravages  of  the  pest,  the  Legislature  appro- 
priates less  than  two-thirds  of  the  sum  which  your  committee,  after 
careful  investigation,  deems  necessary  to  carry  on  the  work,  it  is 
hardly  probable  that  succeeding  Legislatures  would  furnish  the 
means  necessary  to  carry  this  work  to  a  conclusion,  involving  as  it 
would  a  large  outlay  for  many  years  after  the  insect  had  ceased  to 
be  a  pest.  As  I  do  not  believe  that  the  financial  support  would  be 
furnished  you,  I  respectfully  suggest  that  you  consider  the  advisa- 
bility of  adopting  a  different  method  of  combating  the  pest.  Much 
of  the  work  that  is  being  done  now  would  be  unnecessary  if  the 
object  was  merely  to  keep  the  insect  from  being  unduly  destruc- 
tive ;  and,  if  there  is  no  hope  of  your  receiving  the  support  nec- 
essary to  exterminate  the  insect,  the  continuance  of  the  present 
methods  would  certainly  involve  a  large  unnecessary  expenditure. 

It  is  probable  that  if  your  warfare  against  this  insect  was  re- 
stricted to  those  localities  in  which  its  injuries  are  of  a  serious 
nature,  its  natural  enemies  would  greatly  increase  and  tend  to 


APPENDIX.  xlix 

keep  it  in  check.  Already  a  considerable  number  of  parasites  is 
known  to  infest  it.  There  will  be  a  tendency  for  them  to  increase, 
so  that  in  time  serious  outbreaks  of  this  pest  will  probably  be  only 
occasional  and  in  limited  areas.  Such  outbreaks  could  be  easily 
subdued. 

While  I  believe  that  a  change  in  the  object  of  the  work  of  your 
committee  seems  imperative,  I  would  not  consider  for  a  moment 
the  giving  up  of  your  warfare  against  the  pest,  but  would  advise  its 
continuance  in  the  following  manner :  I  would  suggest  no  change 
in  the  organization  for  carrying  on  the  entomological  work  of  the 
State.  A  committee  of  the  State  Board  of  Agriculture,  consti- 
tuted as  is  your  committee,  seems  to  me  to  be  the  most  appropri- 
ate organization  for  this  purpose.  I  would,  however,  recommend 
the  broadening  of  the  scope  of  the  work  of  this  committee,  so  that 
it  should  have  authority  to  deal  with  any  serious  outbreak  of  insect 
pests.  I  will  not  presume  to  indicate  in  detail  the  method  of  con- 
ducting this  work,  beyond  suggesting  that  in  their  more  general 
features  the  horticultural  laws  of  the  State  of  California  might 
serve  as  a  model. 

Very  respectfully,  your  obedient  servant, 

J.    H.    COMSTOCK. 


EXTRACT  FROM  THE  PRESIDENT'S  ADDRESS  BY  L.  O.  HOWARD, 
ENTOMOLOGIST  OF  THE  UNITED  STATES  DEPARTMENT  OF  AGRI- 
CULTURE, DELIVERED  BEFORE  THE  SlXTH  ANNUAL  MEETING  OF 

THE  ASSOCIATION  OF  ECONOMIC   ENTOMOLOGISTS,  BROOKLYN, 
AUG.  14,  1894.* 

The  work  upon  the  gypsy  moth,  by  the  way,  which  has  been 
done  by  the  State  of  Massachusetts  since  1889,  is  one  of  the  most 
remarkable  pieces  of  work,  judging  by  results,  which  has  yet  been 
done  in  economic  entomology.  The  operations  have  been  carried 
on  by  a  committee  of  the  State  Board  of  Agriculture,  and  the 
means  have  been  furnished  by  large  annual  appropriations  by 
the  State  Legislature.  Three  hundred  and  twenty-five  thousand 
dollars  have  already  been  appropriated. 

A  territory  comprising  something  over  one  hundred  square  miles 
was  infested  by  the  insect,  which  occurred  in  such  extraordinary 
numbers  as  to  destroy  many  trees  and  almost  to  threaten  the  ulti- 
mate extinction  of  living  vegetation,  not  only  within  the  infested 

•  Insect  Life,  Vol.  vii.,  No.  2,  page  69. 


1  THE   GYPSY  MOTH. 

territory,  but  in  all  localities  to  which  it  might  spread.  It  is 
unnecessary  to  detail  the  steps  by  which  relief  was  brought  about. 
Mistakes  were  undoubtedly  made  at  first,  and  it  is  to  the  work  of 
the  present  committee  that  the  main  credit  is  due.  The  infested 
territory  has  been  reduced  by  one-half,  and  within  the  districts  in 
which  the  gypsy  moth  at  present  exists  it  is,  practically  speaking, 
a  comparatively  rare  species. 

The  future  of  the  insect  is,  however,  problematical.  The  con- 
tinuance of  sufficiently  large  appropriations  from  the  State  Legis- 
lature to  enable  the  work  to  be  carried  on  on  its  present  scale  is 
doubtful,  and  yet  those  in  charge  believe  that  still  larger  appro- 
priations are  necessary  to  bring  about  extermination.  They  are 
confident,  however,  that  with  sufficient  means, the  insect  can  be 
absolutely  exterminated  from  the  State  of  Massachusetts.  With 
the  Legislature  disinclined  to  continue  the  large  appropriations, 
the  methods  of  the  committee  at  present  pursued  will  have  to  be 
seriously  altered.  Given  a  small  appropriation  of  say  $25,000 
annually,  it  will  become  necessary  to  adopt  some  law,  like  that 
enforced  in  California,  whereby  much  less  frequent  inspection 
may  be  made,  and  the  committee  will  have  to  rely  in  part  upon 
voluntary  observers  for  information.  Moreover,  they  will  be 
unable  to  conduct  spraying  operations  upon  a  large  scale,  and  the 
expense  of  the  destruction  of  insects  will  have  to  be  assessed  upon 
the  owners  of  the  property  upon  which  the  insects  are  found,  pro- 
vided such  owners  will  not  themselves  undertake  the  destruction  of 
the  insects.  There  will  be  many  disadvantages  from  such  a 
course,  and  in  the  case  of  unproductive  lands  the  expense  will  be 
so  great  that  the  owner  will  prefer  confiscation.  Between  some 
such  course  as  this  and  the  continuance  of  the  present  methods, 
however,  there  seems  to  be  little  choice,  since  if  the  appropriation 
were  taken  away  the  insect  will  not  only  speedily  reach  its  former 
destructive  height,  but  will  spread  far  and  wide  over  the  country. 

It  may  be  urged  that  it  will  be  only  a  few  years  before  the  insect 
will  take  its  place  as  a  naturalized  member  of  our  fauna,  and  will 
become  subject  to  the  same  variations  of  increase  and  decrease  as 
our  native  species,  and  that  it  will,  in  fact,  become  little  more  to 
be  feared  than  species  already  existing  with  us,  particularly  if  its 
European  natural  enemies  are  introduced.  Against  this  view, 
however,  it  must  be  urged  that  the  gypsy  moth  seems  an  ex- 
ceptionally hardy  species,  and  that  even  in  Europe  it  is  a  prime 
pest.  The  caterpillar  is  tough  and  rugged,  and  seems  little  sub- 
ject to  disease  and  to  climatic  drawbacks,  and  is  wonderfully  resist- 
ant to  the  action  of  ordinary  insecticides.  The  gypsy-moth  larva 
will  feed  for  days  without  apparent  injury  upon  trees  which  have 


APPENDIX.  li 

been  sprayed  with  Paris  green  or  London  purple  in  a  solution  so 
strong  as  to  somewhat  burn  the  leaves.  In  fact,  the  committee,  in 
the  spraying  which  they  are  carrying  on  at  present,  have  found  it 
necessary  to  use  arsenate  of  lead  in  as  strong  proportion  as  ten 
pounds  to  one  hundred  and  fifty  gallons  of  water.  The  well- 
known  vitality  of  previously  introduced  European  injurious  in- 
sects is  apparently  increased  to  a  striking  degree  by  this  species, 
while  the  fact  that  it  feeds  on  nearly  all  plants  renders  it  a  much 
more  serious  pest  than  any  of  its  forerunners.  Under  these  cir- 
cumstances, therefore,  any  course  other  than  energetic  and  well- 
directed  effort  to  keep  the  insect  within  its  present  boundaries  will 
be  short-sighted  in  the  extreme,  although  it  is  very  doubtful  to  my 
mind  whether  absolute  extermination  will  or  can  ever  be  brought 
about. 


•lii  THE  GYPSY  MOTH. 


APPENDIX  F. 


THE  DANGERS  OF  ARSENICAL  POISONING  RESULTING  FROM 
SPRAYING  WITH  INSECTICIDES. 

Much  has  been  written  in  regard  to  the  supposed  danger  of  fatal 
poisoning  to  the  consumers  of  fruit  which  has  been  gathered  from 
vines  or  trees  which  have  been  sprayed  with  arsenical  mixtures. 
The  fallacy  of  these  ideas  has  been  repeatedly  shown,  and  it  is 
now  well  understood  that  there  is  practically  no  danger  of  fatal 
poisoning  from  eating  sprayed  fruit.  There  are,  however,  other 
dangers,  arising  from  the  widespread  and  careless  use  of  arsenical 
insecticides,  which  have  been  almost  entirely  ignored.  Entomolo- 
gists and  pomologists  officially  connected  with  the  experiment  sta- 
tions of  the  country,  the  agricultural  press  and  writers  of  works 
on  pomology  and  horticulture  all  join  in  recommending  some  of 
the  most  deadly  poisons  as  insecticides ;  but  they  add  scarcely  a 
word  of  caution  in  regard  to  their  use.  "While  the  danger  of  acute 
or  fatal  poisoning,  which  may  arise  from  eating  or  drinking  food 
or  liquids  in  which  Paris  green  or  some  other  form  of  the  arsenites 
has  been  accidentally  mixed,  is  occasionally  pointed  out,  the  evils 
arising  from  contact  with  the  poison  are  seldom  even  noticed. 
Arsenical  preparations  are  applied  broadcast  to  many  cultivated 
crops,  and  few  if  any  precautions  are  taken  against  their  effects 
on  the  human  system.  Paris  green  is  commonly  sold  without  any 
restrictions  whatever,  though  fatal  cases  of  accidental  poisoning 
from  its  use  have  been  frequently  chronicled.* 


*  "  Next  to  arsenious  oxide,  arsenite  of  copper  gives  rise  to  the  largest  number  of 
cases  of  acute  arsenical  poisoning.  This  compound  forms  the  whole  or  a  part  of 
the  pigments  known  as  Scheele's  green  or  Paris  green,  Schweinfurt  or  emerald  green 
(aceto-arsenite  of  copper) .  When  pure,  these  pigments  contain  from  fifty-five  to 
sixty  per  cent,  of  arsenious  acid,  to  which  their  poisonous  properties  are  mainly  due. 
During  the  past  few  years  arsenite  of  copper  has  been  sold  extensively,  under  the 
name  of  Paris  green,  for  the  purpose  of  killing  potato  bugs.  Owing  probably  to 
the  ease  with  which  it  can  be  obtained,  it  has  given  rise  to  a  considerable  number  of 
cases  of  suicidal  poisoning.  Many  cases  of  accidental  poisoning  have  resulted  from 
the  use  of  these  compounds  as  pigments."  (Buck's  "  Reference  Handbook  of 
Medical  Science,"  Vol.  I,  page  344.) 


APPENDIX.  liii 

The  action  of  arsenic  upon  the  human  system  is  poisonous, 
no  matter  how  it  may  find  entrance,  whether  through  the  skin, 
wounds,  the  respiratory  organs  or  the  alimentary  tract.  Nor  are 
the  symptoms  essentially  different,  whatever  its  manner  of  en- 
trance. Thus,  when  applied  outwardly  to  an  abraded  surface,  it 
exerts  a  specific  action  upon  the  mucous  membrane  of  the  stomach. 
Hunter  found  that  the  stomach  of  a  dog  was  considerably  inflamed 
in  an  experiment  in  which  he  applied  arsenic  to  a  wound,  the 
animal  dying  within  twenty-four  hours.  In  other  cases,  upon 
applying  a  bandage  to  prevent  the  dog  licking  the  arsenic  from 
the  wound,  Brodie  found  that  the  inflammation  in  the  stomach  was 
more  acute  and  more  immediate  than  when  the  poison  was  taken 
internally. 

The  curious  fact  that  the  mucous  membrane  of  the  stomach 
inflames  when  arsenic  is  absorbed  from  a  cutaneous  surface  or 
from  a  wound  is  explained  by  the  absorption  of  the  arsenic  into 
the  blood  and  its  separation  from  the  blood  by  the  mucous  mem- 
brane of  the  stomach,  the  arsenic  in  its  passage  exerting  an  irritant 
action. 

According  to  Blyth,  a  quack  applied  an  arsenical  caustic  to  a 
chronic  ulcer,  with  the  result  that  the  patient  was  seized  with 
symptoms  of  violent  poisoning,  and  died  six  days  after  the  appli- 
cation. Blyth  says  such  fatalities  are  frequent. 

The  injurious  effects  produced  by  the  absorption  of  poisons 
through  the  pores  of  the  skin  are  well  known  to  toxicologists  and 
to  the  medical  fraternity.  Cases  where  sudden  death  has  been 
caused  by  the  cutaneous  absorption  of  deadly  mineral  or  vegetable 
poisons  are  on  record.  A  case  is  mentioned  by  Blyth  of  a  woman 
aged  fifty-one  years,  who  died  after  a  protracted  illness,  the  result 
of  using  a  solution  of  arsenious  acid  to  cure  the  itch.*  Less 
serious  attacks  of  poisoning  are  not  very  uncommon  among  those 
who  use  arsenic,  while  continued  exposure  to  the  influences  of 
mineral  poisons  often  produces  symptoms  of  chronic  poisoning. 

"The  arsenical  pigments  more  frequently  give  rise  to  external 
local  eruptions  and  chronic  poisoning  than  to  acute  poisoning."! 

The  first  symptoms  of  chronic  arsenical  poisoning  result  from 
the  local  action  of  the  arsenic.  Externally  they  consist  of  cutane- 
ous irritations,  eruptions  and  even  ulcers  on  the  various  exposed 
portions  of  the  body.  The  eruption  of  the  face  is  sometimes 
so  serious  as  to  render  the  victim  unrecognizable.  Inflammation 


*  "  Poisons,  their  Effect  and  Detection,"  A.  W.  Blyth. 

t  "  Reference  Handbook  of  Medical  Science,"  Vol.  I,  page  344. 


liv  THE   GYPSY  MOTH. 

of  the  scrotum,  sometimes  resembling  hydrocele,  is  a  frequent 
symptom,  and  this  inflammation  extends  to  the  adjacent  parts. 
There  is  frequently  an  irritation  of  the  mucous  membrane  of  the 
eye,  also  oedema  of  the  eyelids.  This  conjunctival  inflammation  is 
manifested  by  redness  and  an  intolerance  o«f  light.  Other  inflam- 
mations of  the  mucous  membrane,  resulting  in  irritation  of  the 
nasal  passages  and  throat,  dry  cough,  loss  of  appetite,  thirst, 
nausea,  a  feeling  of  uneasiness  or  pain  in  the  stomach  and 
intestines,  and  sometimes  vomiting  and  diarrhoea  ensue.  Often 
these  symptoms  are  not  very  severe,  but  they  are  sometimes  con- 
tinued for  a  long  period,  and  in  a  few  cases  they  have  resulted 
fatally.  Other  symptoms  sometimes  produced  by  the  constitu- 
tional action  of  the  poison  are  headaches,  sleeplessness,  muscular 
debility,  emaciation,  depression  of  spirits,  neuralgic  pains  in 
various  parts  of  the  body,  muscular  trembling,  occasional  con- 
vulsions and  paralysis  of  the  extremities.  It  is  said  that  fatty 
degeneration  of  the  liver,  kidneys  and  other  organs  sometimes 
takes  place  by  a  process  analogous  to  that  caused  by  the  action 
of  phosphorus.* 

The  effects  of  the  arsenical  preparations  when  taken  internally 
are  well  known,  but  the  dangers  arising  from  their  absorption  and 
inhalation  are  not  generally  understood.  Many  people  who  have 
been  accustomed  to  using  arsenic  in  some  process  of  manufacture 
or  trade  have  occasionally  suffered  from  acute  attacks  of  arsenical 
poisoning  without  being  aware  of  the  real  cause  of  their  sufferings. 
Others,  who  have  suffered  for  years  from  chronic  arsenical  poison- 
ing, being  ignorant  of  the  cause  of  their  symptoms,  have  neglected 
to  remove  it,  and  have  attributed  their  condition  to  other  agencies 
or  to  disease.  The  inflammation  of  the  mucous  membrane  of  the 
nasal  passages  and  throat  is  often  attributed  to  catarrh,  while 
the  trouble  with  the  stomach  and  intestines  is  usually  attributed 
to  dyspepsia.  Amateur  and  professional  taxidermists,  especially 
those  who  use  white  arsenic  in  its  dry  form,  sometimes  suffer  from 
all  the  symptoms  of  both  acute  and  chronic  poisoning.  Not  in- 
frequently the  death  of  taxidermists  is  caused  or  hastened  by  the 
use  of  arsenic.  In  one  case  a  taxidermist  was  rendered  almost 
totally  blind  for  a  considerable  period  by  the  use  of  arsenic. 

Browne  mentions  a  case  of  a  man  who  formerly  used  dry 
arsenic  in  preserving  natural  history  specimens,  and  whose  con- 
stitution was,  he  says,  thoroughly  broken  up  by  it.  An  amateur 
of  long  standing  became  paralyzed  in  one  hand.  This  man  was 


•  "  Poisons,  their  Effect  and  Detection,"  Vol.  II,  page  495. 


APPENDIX.  Iv 

not  aware  of  the  source  of  his  trouble,  and  had  never  mentioned 
the  fact  of  his  using  arsenic  to  his  numerous  physicians,  who  had 
therefore  worked  in  the  dark  as  to  the  real  cause  of  his  condition.* 
Mr.  C.  J.  Maynard,  author  of  the  "Naturalists'  Guide,"  " Birds 
of  Eastern  North  America "  and  other  works,  was  at  one  time  so 
seriously  affected  by  the  arsenic  used  in  the  preparation  of  skins 
of  birds  and  mammals  that  he  was  obliged  to  discard  the  pre- 
servative, suffering  for  several  years  from  the  symptoms  of 
chronic  arsenical  poisoning.  Workmen  in  factories  where  arsen- 
ical preparations  are  made  frequently  suffer  from  arsenical  poison- 
ing, either  acute  or  chronic,  and  fatal  cases  are  on  record.  Some 
of  the  men  employed  in  handling  arsenate  of  soda,  Paris  green 
and  other  insecticides  in  the  storehouse  connected  with  the  gypsy 
moth  work  have  been  somewhat  affected  by  arsenical  poisoning. 
The  effect  of  poisoning  from  arsenical  wall  paper  is  well  known. 

The  cases  of  poisoning  so  far  given  are  those  of  people  who 
have  been  exposed  to  the  dust  or  fumes  of  arsenic  in-doors.  It 
might  be  thought  that  persons  working  out  of  doors  would  not 
be  similarly  affected.  Out-door  conditions,  such  as  atmospheric 
currents  and  sunlight,  may  lessen  the  danger  of  poison  by  inhala- 
tion. Yet  arsenic,  being  chemically  unchangeable  and  its  poi- 
sonous properties  not  being  affected  by  light,  air  or  water,  has 
practically  the  same  effect  when  brought  in  contact  with  the  skin 
or  mucous  membranes,  whether  the  person  using  it  is  out-doors  or 
in-doors.  Among  the  workmen  employed  in  the  manufacture  of 
an  arsenical  green  which  is  obtained  from  arsenite  of  soda  by 
treating  it  with  sulphate  of  copper  and  then  with  pyroligneous 
acid,  the  symptoms  of  arsenical  poisoning  are  very  marked.  The 
process  of  manufacture  usually  takes  place  in  the  open  air.  The 
evil  consequences  of  working  over  the  mixture  appear  in  boils, 
pimples  and  an  itching  rash  about  the  nostrils  and  in  the  flexures 
of  the  arms.  In  severe  cases  headache,  thirst  and  nausea  occur. 
Eruptions  on  the  hands,  face  and  other  exposed  parts,  ulcers  in 
the  groin  and  other  symptoms  of  arsenical  poisoning  by  absorp- 
tion are  not  uncommon  among  those  who  use  Paris  green  in  the 
field,  either  in  spraying  trees  or  in  dusting  the  poison  over  pota- 
toes or  other  field  crops. 

In  these  cases  poisoning  is  probably  caused  by  the  absorption 
through  the  pores  of  fine  arsenical  dust  or  spray,  floating  in  the 
atmosphere,  or  by  the  absorption  of  particles  of  arsenic  which 
reach  the  hands,  face  and  other  portions  of  the  body  in  various 

»  Montague  Browne,  "  Practical  Taxidermy,"  pages  66,  67. 


Ivi  THE  GYPSY  MOTH. 

ways.  The  absorption  of  the  poison  is  likely  to  be  greater  when 
the  subject  is  perspiring  freely,  and  the  danger  is  greatest  when 
one  is  handling  a  form  of  arsenic  which  is  more  or  less  readily 
soluble.  Therefore  the  danger  in  handling  arsenate  of  soda, 
London  purple  or  white  arsenic  is  probably  greater  than  that  in 
handling  Paris  green  or  arsenate  of  lead ;  yet  serious  effects  may 
in  time  be  produced  by  either  of  these  latter  poisons,  and  they 
should  be  always  used  with  the  greatest  care.  The  danger  of 
poisoning  by  respiration  is  probably  greatest  when  the  insecticide 
is  used  in  the  form  of  a  powder  and  thrown  broadcast  in  air, 
although,  if  the  poison  is  mixed  in  water  and  a  fine  spray  is 
allowed  to  drift  over  the  person,  a  small  amount  may  be  inhaled. 
In  either  case  the  effects  of  the  poison  inhaled  will  be  felt  first  in 
the  mouth,  nasal  passages  and  throat. 

The  danger  of  poisoning  by  spraying  is  increased  in  the  case 
of  some  individuals  by  their  peculiar  susceptibility  to  the  effects 
of  the  poison.  The  difference  in  susceptibility  to  these  poisons 
shown  by  different  individuals  under  the  same  conditions  is  re- 
markable. It  is  possible  that  some  persons  may  gradually  become 
accustomed  to  the  use  of  arsenic,  and  eliminate  from  the  system, 
without  experiencing  ill  effects,  an  amount  of  poison  which  would 
prove  very  injurious  to  others  more  susceptible  to  its  influence. 
Some  people  who  have  once  suffered  from  the  symptoms  of  chronic 
arsenical  poisoning  exhibit  a  marked  susceptibility  to  the  effects  of 
arsenic  for  years  afterward. 

During  the  spraying  in  1891  two  cases  were  known  where 
women,  in  whose  faces  a  spray  of  Paris  green  was  accidentally 
blown  by  the  wind,  were  immediately  affected  with  a  burning 
sensation  of  the  skin,  followed  soon  after  by  eruptions.  An 
elderly  woman -who  was  also  exposed  to  the  spray  suffered  from 
arsenical  poisoning  to  such  an  extent  that  she  required  the  services 
of  a  physician  for  a  considerable  period.  Her  symptoms  appeared 
to  arise  from  this  exposure. 

It  is  not  generally  known  that  serious  effects  sometimes  follow 
poisoning  from  arsenical  spraying.  Though  there  is  ordinarily 
little  danger  from  the  spraying  of  a  few  trees,  even  this  may  be 
dangerous  to  one  peculiarly  susceptible  to  the  action  of  the  poison. 
In  such  a  case  complete  prostration,  inflammation,  serious  ulceration 
of  the  face  and  mouth  and  other  parts  of  the  body,  suppuration, 
copious  salivation  and  delirium  have  followed  within  a  few  days. 
A  case  of  arsenical  poisoning  resulting  fatally  to  an  elderly 
farmer  has  recently  been  reported.  In  this  case  death  is  said  to 


APPENDIX.  Ivii 

have  been  caused  or  hastened  by  his  spraying  orchard  trees  for 
several  years  in  succession  with  Paris  green.  If  the  poison  comes 
in  contact  with  wounds  or  abrasions  of  the  skin,  ulcers  are  some- 
times formed  which  will  not  heal  until  spraying  is  given  up. 
Symptoms  of  a  mild  form  of  this  poisoning  resemble  those  pro- 
duced by  the  poison  ivy  (Rhus  toxicodendron) ,  and  sprayers  who 
are  poisoned  usually  attribute  their  symptoms  to  that  cause. 
While  serious  poisoning  from  spraying  is  rare,  the  mild  syaap- 
toms  are  quite  frequently  shown ;  and  in  some  cases,  if  spraying 
is  done  continuously  for  a  considerable  period  of  time,  chronic 
poisoning  will  result.  There  is  probably  little  danger  of  fatal 
poisoning  except  in  cases  of  invalids  or  elderly  people. 

In  spraying  with  arsenites,  serious  effects  may  usually  be  avoided 
by  using  the  following  precautions :  cover  any  wound  or  abrasion  of 
the  skin,  so  that  the  insecticide  cannot  come  in  contact  with  it ; 
when  spraying  with  an  extension  nozzle  or  pole,  use  an  elongated 
leather  washer  below  the  nozzle,  so  as  to  carry  off  the  drip ;  wear 
rubber  clothing  and  a  rubber  or  oil  hat  of  the  shape  of  a  "  sou- 
wester"  or  tarpaulin,  and  take  care  to  stand  as  far  as  possible 
to  windward  of  the  spray.  The  face  and  hands  should  be  thor- 
oughly washed  immediately  after  spraying,  and  the  entire  body 
should  be  bathed  daily. 

The  usual  treatment  for  arsenical  poisoning  is  well  known  to 
medical  men.  An  antidote  for  local  external  poisoning  not  gener- 
ally known  is  acetate  of  lead,  commonly  called  sugar  of  lead.  A 
strong  solution  of  this  in  water  will  allay  serious  inflammations 
of  the  skin,  caused  by  arsenical  poisoning,  but  it  should  only  be 
applied  externally,  and  even  then  with  care,  as  it  possesses  poison- 
ous properties. 


Iviii 


THE   GYPSY   MOTH. 


APPENDIX    Gr. 


A  LIST  OF  EESIDENTS  OF  THE  INFESTED  DISTRICT  WHO 
HAVE  FURNISHED  INFORMATION  IN  REGARD  TO  THE 
GYPSY  MOTH  IN  MASSACHUSETTS. 

Statements  in  regard  to  the  ravages,  habits  and  spread  of  the 
gypsy  moth  or  the  work  of  destroying  it  in  Massachusetts  have 
been  received  from  citizens  whose  names  appear  below.  Lack  of 
space  has  made  it  impossible  to  print  these  statements,  but 
extracts  from  some  of  them  will  be  found  in  Part  I. 


Arlington  :  — 

Chelsea  :  — 

Medford  —  Con. 

Benjamin  Campbell. 

J.  T.  Bond. 

Mrs.  J.  H.  Archibald. 

H.  A.  Fernald. 

Martin  Curley. 

Geo.  H.  Bean. 

Chas.  A.  Greene,  M.D. 

J.  Waldo  Denny. 

James  Bean. 

Belmont  :  — 

L.  E.  H.  Jones. 

Mrs.  Wm.  Belcher. 

Mrs.  Edwin  F.  Atkins. 

Wm.  Jones. 

Mrs.  John  Benson. 

Edward  W.  Brown. 

S.  Kimball. 

Almon  Black. 

W.  L.  Chenery. 

Everett  :  — 

Miss  A.  B.  Bockman. 

Thomas  L.  Creeley. 

Timothy  Murphy. 

Mrs.  John  Brown. 

Irving  B.  Frost. 

Lynn  :  — 

Oran  Brown. 

C.  F.  and  R.  Hittinger. 

J.  G.  Olin. 

Miss  Charlotte  E.  Camp. 

Daniel  F.  Learned. 

Maiden:  — 

E.  Clark. 

Oilman  Osgood. 

Mrs.  Peter  Campbell. 

J.  C.  Clark. 

James  K.  P.  Sargent. 

Michael  Cleary. 

L.  M.  Clifford. 

Edward  Skahan. 

Mrs.  Margaret  Connell. 

J.  S.  Cotton. 

John  W.  Skahan. 

Mrs.  M.  Cronin. 

W.  C.  Craig. 

Merton  Simonds. 

Richard  Dexter. 

John  Crowley. 

J.  0.  Wellington. 

Mrs.  John  Dowd. 

A.  W.  Crockford. 

Chas.  W.  Winn. 

James  F.  Eaton. 

D.  W.  Daly. 

Boston  :  — 

Mrs.  J.  W.  Flinn. 

J.  P.  Dill. 

J.  B.  Alden. 

Mrs.  Daniel  Kelly. 

C.  R.  Drew. 

John  A.  Bruen. 

Wm.  McLaughlin. 

Mrs.  G.  H.  Dudley. 

Mrs.  T.  J.  Lane. 

T.  J.  Neville. 

Mrs.  J.  E.  Fairbanks. 

A.  L.  McCormack. 

Miss  Abbie  Sullivan. 

Mrs.  M.  F.  Fenton. 

Wm.  Tyner. 

Mrs.  B.  Wallace. 

Mrs.  S.  J.  Follansbee. 

Cambridge  :  — 

Medford  :  — 

F.  E.  Foster. 

Wm.  H.  Eveleth. 

Miss  R.  M.  Angelbeek. 

J.  T.  Foster. 

APPENDIX. 


lix 


Medf  ord  —  Con. 

Medford  —  Con. 

Somerville  :  — 

J.  N.  French. 

G.  C.  Russell. 

J.  H.  Cahalan. 

11.  Gibson. 

Mrs.  P.  N.  Ryder. 

Asa  Durgin. 

F.  M.  Goodwin. 

Miss  Z.  Sawyer. 

Thos.  H.  Eames. 

J.  0.  Goodwin. 

Japhet  Sherman. 

Sarah  E.  Fisk. 

N.  P.  Hallowell. 

Walter  Sherman. 

Albert  Kenneson. 

Mrs.  I.  W.  Hamlin. 

Mrs.  W.  H.  Snowdon. 

F.  L.  Newton,  M.D. 

J.  W.  Harlow. 

Mrs.  F.  T.  Spinney. 

I.  L.  Russell. 

Wm.  B.  Harmon. 

Wm.  R.  Taylor. 

Swampscott  :  — 

Fred  H.  Haushalter. 

Mrs.  R.  Tuttle. 

A.  R.  Bunting. 

E.  G.  Holmes. 

Geo.  H.  Webster. 

Jas.  Pitman. 

John  Hutchins. 

J  E.  Wellington. 

Wakefield:  — 

A.  R.  Kervin. 

S.  F.  Weston. 

J.  H.  Carter. 

Sylvester  Lacy. 

John  G.  Wheeler. 

Rufus  Kendrick. 

Mrs.  Chas.  A.  Lawrence. 

Miss  H.  T.  Wild. 

Watertown:  — 

Edward  Loeffler. 

Melrose  :  — 

M.  W.  Chadbourne. 

Mrs.  Thomas  F.  Mayo. 

Henry  Lynde. 

Nathan  Drake. 

Miss  R.  A.  McCarty. 

Mrs.  E.  A.  Mansfield. 

J.  W.  Lovering. 

Mrs.  E.  E.  Merrill. 

Mrs.  A.  C.  Peyser. 

J.  E.  Skinner. 

J.  C.  Miller,  Jr. 

Revere  :  — 

Samuel  Walker. 

A.  P.  Perry. 

J.  W.  Copeland. 

Solon  F.  Whitney. 

Mrs.  F.  P.  Peirce. 

S.  S.  Pratt. 

Winchester  :  — 

Richard  Pierce. 

Benj.  Shurtleff. 

Louis  Goddu. 

Mrs  A.  H.  Plummer. 

Josiah  B.  Shurtleff. 

H.  W.  Eight. 

Mrs.  M.  M.  Ransom. 

Salem  :  — 

Chas.  R.  Mason. 

Wm.  S.  Richards. 

Geo.  W.  Creesy. 

W.  D.  Sanborn. 

D.  M.  Richardson. 

Saugus:  — 

Winthrop:— 

Jotham  H.  Rogers. 

L.  Mansfield. 

F.  W.  Belcher. 

Mrs.  E.  M.  Russell. 

W.  H.  Penny. 

Chas.  BurrilL 

INDEX 


A. 

PASS 

Abundance  and  destructiveness  of  the  gypsy  moth,  ....  40 

Acclimation  of  the  gypsy  moth, 94 

Achcetoneura  fernaldi,  .........  387,  392 

Acids  used  for  destroying  eggs, 63,  123,  413,  416 

Act  to  provide  against  depredations  by  the  gypsy  moth,  . .  .  .  36,  47 
Adviser,  entomological,  Prof.  C.  H.  Fernald  appointed,  ...  57 

^rostatic  hairs, 301 

Africa,  occurrence  of  gypsy  moth  in, 267 

Agalena  ncevia 405 

Age  of  egg-clusters,  how  determined, 95 

of  new  colonies, 70,  80 

Alarms,  false, 201 

Albrecht  on  distribution  of  gypsy  moth, 268 

Aletia  argillacea 325 

Algiers,  occurrence  of  gypsy  moth  in, 267 

Alisma  plantago  as  a  food  plant, 317 

Altum,  Dr.  Bernard,  advice  concerning  importation  of  parasites,  .  288 

on  value  of  birds, 211,  232 

America,  importation  of  gypsy  moth  into, 3 

importation  of  English  sparrow  into, 233 

occurrence  of  gypsy  moth  in,  recorded  by  Professor  Kiley,  .  .8 
American  redstart  attacking  the  gypsy  moth, 208 

robin  attacking  the  gypsy  moth, 208 

Ammonia,  eggs  treated  with, .  .407 

Amount  of  food  consumed  by  caterpillars, 315 

Anabrus  simplex,  destruction  of  crops  by,  ......      206 

Analyses  of  Paris  green, 492 

of  Paris  green  and  lime, .      493 

of  poisoned  larvae, 474 

Anatomy  of  the  gypsy  moth,  external,  .  .  .  .  .  .  339 

of  the  gypsy  moth,  internal, .        .......      368 

Anderson  Brick  Company,  shipments  from,        .        .        .        .        .       110 

Anderson  on  ravages  of  gypsy  moth  in  Shipov,          ....      282 

Angelbeek,  Miss  R.  M.,  statement  of,         .....     20,  27,  29 

Animals,  distribution  of  the  gypsy  moth  by,  .  ...  •  •  103 

injured  by  spraying, »  .  161 

Anisocyrta  sp., 375 


Ixii  THE   GYPSY   MOTH. 

PAffK 

Anisota  senatoria, 400,  402 

Anisopteryx pometaria  destroyed  by  chickadee, 204 

food  plants  of, 97 

Annual  inspection,  the, 196 

Antennae  of  gypsy  moth, 339 

function  of, 356 

Anthrenus  scrophularice,  damage  from, 270 

Antinonnin 479 

Ants  attacking  female  moths, .       364,  380 

Apanteles,  species  parasitic  on  gypsy  moth  in  Europe,        .         .        .378 

Apple  trees  attacked  by  gypsy  moth  in  Europe 277 

trees  injured  by  bad  pruning, 174 

trees,  leaf  area  of, 495 

Appleton,  F.  H.,  at  conference  on  gypsy  moth  (Appendix  A). 

member  of  committee, 49,  76 

resignation  from  committee, 77 

visit  to  Washington, 83 

Appropriation,  balance  of,  on  hand  Jan.  1,  1894,        ....        72 

efforts  to  secure  an,  from  Congress, 83 

expended  by  first  commission 73 

expended  by  second  commission, 73 

insuflftcient, 39,  61,  64,  69,  87,  88 

loss  by  delay  of 63,  68,  78,  79,  84,  85 

necessity  of,  in  order  to  inspect  woodland, 80 

Appropriations,  yearly 36,  39,  49,  63,  68,  77,  84 

Area,  infested.     See  Infested  region. 

leaf,  of  trees, 494 

spiny,  of  wings  of  gypsy  moth,    .        .        .  .        .        .      341 

Argyrophylax  gilva, .        .        .       392 

Arlington,  area  of  woodland  infested  in,     .        .        ...        •        •        87 
gypsy  moths  found  in,  .         .         .        ...        .        .        .        58 

petition  presented  by  selectmen  of, 36 

Army  worm,  cyclone  burner  recommended  against,    ....      121 
gypsy  moth  mistaken  for,      .         .        .        .        .        .        .        .        33 

Arsenate  of  lead 69,  80,  87,  142,  143,  145,  449,  473,  449 

of  soda,  experiments  with,    .        .        .  *     »        .        .        .        .       143 
of  zinc,  experiments  with,     .  •       .        .        .        .        .        .        .      480 

Arsenic  as  an  insecticide, ,  ,        »        .        .      481 

effects  of, ....       .        .162 

Arsenical  poisoning  (Appendix  F). 

poisons,  comparative  effects  of, .      473 

effects  on  foliage 489 

spraying  with, 65,  417 

Arsenites,  entomologists  recommend  spraying  with 45 

Ash,  exempt  from  ravages  of  gypsy  moth  in  Russia,  .        .        .       282 

Asia,  distribution  of  gypsy  moth  in, 267 

Asilus  sericeus, 392 

Aspens  attacked  by  gypsy  moth, 277 

Assembling  of  the  gypsy  moth, 342,  345 

power  of  pupae, 363 

Atlanta  Exposition,  exhibit  at, '.       .        .      201 


INDEX.  Ixiii 


PAGE 

Attacus  cecropia, 387,  402 

promethea, 402 

Aughey,  Prof.  Samuel,  experiments  on  plover, 204 

on  birds  v.  locusts,  .  .  .  ....  .  .  205 

Australia,  importation  of  rabbits  into,         .        .        .        .        .         .233 

importation  of  sparrow  into,  . 233 

Avery,  John  G.,  elected  member  of  gypsy  moth  committee,      .        .        84 

B. 

Bacteria,  aid  rendered  by 288 

occurring  in  larval  stomach, .      369 

Bailey,  C.  E.,  observation  on  birds  distributing  the  gypsy  moth,       .       236 

observation  on  Cimbex  americana, 379 

observation  on  cuckoo, 212 

observation  on  downy  woodpecker, 221 

observation  on  egg-feeding  birds, 229 

observation  on  Theronia  melanocephala, 376 

observation  on  vireos, 222 

observation  on  warbler, 219 

Baltimore  oriole  attacking  the  gypsy  moth,         ....       213,  225 

Bands,  burlap, 167 

pitch, 285 

raupenleim, 64,  129,  195 

tar, 285,  286 

tree  ink, 64,  128 

wadding 127,  285 

Barrett,  C.  G.,  on  disappearance  of  gypsy  moth  in  England,     .        .      270 

Bavaria  invaded  by  nun  moth, 208 

Bay  State  Brick  Company,  shipments  of  wood  to,      .        .        .        .111 

Bazin  on  ravages  of  gypsy  moth  in  France, 277 

Bean,  James,  statement  of, 20,  29 

Bechstein  on  egg  killing, 117 

on  ravages  of  gypsy  moth, 275 

Bees,  danger  to,  from  spraying, 157 

Beetles,  cages  for  breeding, 384 

predaceous, .   ...    _   .381 

Belcher,  Mrs.  William,  statement  of,  ...,.-        8,11,17,26 
Beling,  Theodore,  on  methods  of  destroying  the  gypsy  moth,   .         .      285 
Belmont,  colonies  found  in,          .         ........         47 

Benson,  Mrs.  John,  statement  of,        .        .        ...        .        .19,27 

Benzine,  eggs  treated  with, .        .        .        ....        .        .        .      408 

Berlin,  occurrence  of  gypsy  moth  at,  .        .        »        .        .        .       274,  277 
Bibliography  of  gypsy  moth,        .        .        .        .        .        .        .        257-267 

Birch  attacked  by  gypsy  moth  in  Europe, 277,  282 

Birds  as  destroyers  of  locusts,      .        .        .        .        .        .        .        .      205 

attacking  the  gypsy  moth,     .        .        ...        .        .        .       207 

attracted  to  infested  localities,      .        .    " 223 

destroyed  for  milliners, .        .        . 243 

destruction  of  canker  worms  by, 96 

destruction  of  parasites  by,  . 240,  376 


Ixiv  THE  GYPSY  MOTH. 


PAGE 

Birds,  distribution  of  gypsy  moth  by,          ...  98,  214,  231,  235,  239 

European,  introduction  of, 232 

feeding  on  the  caterpillars, 6,  96,  209,  228 

feeding  on  female  gypsy  moth, 228 

feeding  on  male  gypsy  moth, 228 

feeding  on  the  pupae  of  the  gypsy  moth,       .        .        i    '    .        .      228 

folly  of  destroying, .        .        .205 

most  useful  as  moth  destroyers, 210 

native,  driven  away  by  English  sparrows 234 

protection  of, 242 

that  may  devour  gypsy  moth  eggs, 228 

value  of, 203 

value  of,  in  Europe, 284 

v.  useful  insects, 240 

Black,  Almon,  statement  of, 20,  24,  28 

Black-and-white  warbler  attacking  the  gypsy  moth,  .         .        .       208,  225 
Black-billed  cuckoo  attacking  the  gypsy  moth,  ....       207,  212 

Blackbird  attacking  the  gypsy  moth, 207 

value  of, 204 

Black-throated  green  warbler  attacking  the  gypsy  moth,  .        .        .      208 

Bluebird  attacking  the  gypsy  moth, 208,  218,  227 

driven  away  by  sparrows, 234 

Blue-jay  attacking  the  gypsy  moth, 6,  207,  225 

distributing  the  gypsy  moth, 236 

Board  of  Agriculture,  State,  advice  of,  concerning  extermination,   .        70 

amount  expended  by,  in  1891,  1892,  1893, 74 

appropriations  recommended  by, 62,68,77,84 

bulletin  issued  by, 56 

conference  at  office  of 45 

extracts  from  reports  of  the,          ....          65-67,78,81,82 
petition  for  an  additional  appropriation  by  the  executive  com- 
mittee of, 78 

reorganization  of,  suggested  by  Wm.  H.  Bowker,        ...        83 

special  meeting  of,  '. 49 

supersedes  commission  of  1891, 47 

Boards  of  health,  information  furnished  by 107 

Bockman,  Miss  A.  B.,  statement  of, 20 

Bombycidae,  assembling  in  the,    .         .        .        '.        .        .        .        .      357 

Books,  section,  record  of  infested  estates  kept  in,      ....        52 

Boston  &  Maine  Railroad,  inspection  of,      .        .        .        .        .        .111 

Boston,  danger  from  traffic  to,    .        .        .        ....        .        .      107 

gypsy  moth  found  in,     .        .        .        .        .        .        .        .        .  70,  80 

result  of  inspection  of,  in  1894,     ....;...        80 

Bowker,  Wm.  H.,  elected  a  member  of  the  committee,      ...        76 
reorganization  of  State  Board  of  Agriculture  suggested  by,        .        83 
retirement  of,  from  State  Board  of  Agriculture, ....        83 

Brackett,  Gov.  J.  Q.  A.,  commission  appointed  by,    ....        38 

extract  from  message,   ." 35 

Bradley,  J.  Howard,  appointed  commissioner, 38 

Branches,  how  broken, 174 

removal  of, 182,  184 


INDEX.  Ixv 


PAGE 

Breeding  cage  for  predaceous  insects, 384,  395 

Bremer  on  distribution  of  gypsy  moth, 267 

Brick  shipments,  inspection  of, 110 

Bromine  used  on  eggs,         .        ...        .        .        .         63,  125,  408 

Brood,  second,  of  gypsy  moth,    .        .        .        .        .        .        .         86,295 

Brown,  Thomas,  on  ravages  of  gypsy  moth  in  France,       .        .        .274 
Brown  thrush  attacking  the  gypsy  moth,    ...      .        .        .       208,  225 

Brush,' cutting  and  burning 85,167,193 

Brussels,  ravages  of  gypsy  moth  in, .279 

Buffalo  carpet  beetle,  damage  from, 270 

Bufo.lentiginosus,          .  .        .        .  ,.  .        .        .        .      404 

Bugs,  predaceous .        .        .       241,  392 

Buildings,  comparison  of  yearly  work  on 93 

Bulletin  of  information,  publication  of,       ....   34,  56,  199,  200 
Bullock,  Representative  W.  J.  D.,  order  presented  by,      ...        72 

Bunting,  towhee,  attacking  the  gypsy  moth, 225 

Burlap,  .         .         .57,  64,  69,  79,  114,  167,  168,  169,  170,  188,  213,  291,  335 

Burner,  cyclone, 121 

naphtha, 122 

Burning,  caterpillars  killed  by,    .        .         .        .        57,  58,  59,  87,  126,  165 

hollow  trees 121 

machines, 119-121 

of  eggs, 57,  118 

of  foliage  by  arsenites .       159,491 

pupae,     .        .        . .        .        80 

rubbish 193 

Burrelle,  on  use  of  burlap 171 

c. 

Cabbage  butterfly,  damage  from, 270 

Cadey,  E.  J.,  statement  of, 40 

Cages  for  breeding  predaceous  insects,        .....       384,  395 

Calcic  chloride,  eggs  treated  with,       .        .        .  .        .        .409 

Calosoma  calidum,         .        .        .       v.        .        .      ..       ,.  ,      .       381,383 

frigidum, .-..»...        .        .      383 

inquisitor •, .287 

scrutator, 382 

sycophanta,    .        .        .  .        .        ...        .       287,  385 

Camp,  Miss  C.  E.,  statement  of, 26 

Camponotus  pennsylvanicus, 364,381 

(herculaneus,} 405 

Campoplex  conicus 378 

difformis,      .         .         .        •  •  .   • 378 

Canker  worms  destroyed  by  birds, 96,  204,  219 

destroyed  by  spraying, .*  .140 

importation  of  sparrows,  against, 233 

influence  on  destruction  of  gypsy  moth  caterpillars,    .        .        .222 

Cannon,  Hon.  George  Q.,  on  cricket  ravages, 206 

Carabus  serratus, 383 

Carbolic  acid  for  destroying  eggs, 123 


Ixvi  THE   GYPSY   MOTH. 


PAGE 

Carbon  bi-sulphide,  eggs  treated  with 408 

Carlier  on  parthenogenesis, 366 

Carpenter,  F.  B.,  cotton  plants  received  from,    .....      324 

Carpocapsa  pomonella  taken  under  burlaps, 171 

Castor  oil  on  eggs, 417 

Catbird  attacking  the  gypsy  moth, 6,208,213 

destruction  of  silkworms  by,         .        .        .        .        .'•"•.        .          6 

feeding  habits, .        .237 

Caterpillars  of  the  gypsy  moth  attacked  by  Polistes  pallipes,       .        .       378 

attacked  by  predaceous  bugs, 392 

attracted  to  light, 310 

become  a  serious  nuisance, 14 

comparison  of  numbers  of,  destroyed  annually,  ....        93 

description  of , 300 

destroyed  by  birds, 7,  96,  209,  228 

destruction  of,  by  burning 57,  58,  59,  87,  126,  165 

destruction  of,  by  spraying, 58 

detrimental  to  real  estate, 21 

disease  among, 280 

distance  travelled  by 58,  310 

distributed  by  birds, 214,  236 

distributed  by  spraying, 113 

distribution  of, 54,58,97,112 

effect  of  cold  on, 96,  328 

effect  of  heat  on, 96,  327 

European  methods  for  destroying, 117,284 

expense  of  destroying, 79 

feeding  habits  of , 311 

feeding  on  cotton  plant, 324 

first  and  last  appearance  of, 304 

food  selection  by, 485 

found  on  vehicles, 39 

indications  of  presence  of, 86 

insecticides  for  destroying, 137,  417,  477 

killed  by  spraying, 57,  64 

length  of  life  of  the, 96,  306 

loss  of  weight  in  pupating, 333 

means  of  preventing  spread  of,    .......        63 

molting  of, 304,308 

not  affected  by  insecticides, 157,  474 

number  from  single  egg-cluster, 94,  297 

number  greatly  reduced  by  exterminative  methods,  .        .        CO 

obstruct  railroad  trains  in  Europe,        .        .  .         .        .280 

places  of  pupation,         .         .        ....     -:•,        .        .        .       335 

poisoned,  analyses  of, 474 

prevented  from  ascending  trees, 64 

scattering  of.     See  Distribution. 

spinning  habits  of, 102,  330 

sprayed  with  contact  insecticides,         ....          57,  163,  485 
spread  of,  injury  caused  by 59 


INDEX.  Ixvii 


PAGE 

Caterpillars  of  the  gypsy  moth  taken  under  burlaps,  .        .        .        .114 

traps  for,        .        . 170,  311 

value  of  burlap  against, 169 

vitality  of, 98,325 

Caucasus,  The,  occurrence  of  the  gypsy  moth  in 268 

Cement,  use  of,  on  trees, 40,  172,  187,  188 

Ceylon,  occurrence  of  gypsy  moth  in,  .        .        .        .        .      267 

Chcetomyia  crassiseta, 392 

Chelsea,  outbreak  of  the  gypsy  moth  in, 58 

Chemicals  for  killing  eggs, -       .        .       122,407 

Chestnut-sided  warbler  attacking  the  gypsy  moth,     ....      208 

Che  wink  attacking  the  gypsy  moth,     .         .        .        .        .        .       207,219 

Chianti,  ravages  of  the  gypsy  moth  in,        .        .        ;        .        .        .      279 
Chickadee,  destruction  of  gypsy  moth  by,  .     208,  210,  214, 224, 227,  231, 236 

feeding  habits  of, 230,  237 

China,  North,  occurrence  of  the  gypsy  moth  in,          ....      268 
Chipping  sparrow  attacking  the  gypsy  moth,      .        .        207,  215,  226,  227 

Chlorine  used  on  eggs, 63,  125,  408 

Chloro  naptholeum,  experiments  with, 481 

Chrysomela  scalaris  attacking  elm  trees, 235 

Chrysopa  sp., 405 

Cicindela  6-guttata,   ' • 405 

Cimbex  americana, 379,  402 

Circumstances  favoring  extermination, 244 

Cities  and  towns  from  which  false  alarms  have  been  received, .        .       201 

beyond  infested  area,  inspected, 198 

Citizens,  assistance  of,  in  destroying  the  gypsy  moth,       .       34,  68,  77,  84 
of  Medford  on  escape  of  the  gypsy  moth,     .        .        .        ,        .4 

Clark,  J.  C.,  statement  of, 19,24,31 

Cleaning  knives, 126 

Clercy,  J.  O.,  on  birds  v.  insects, 205 

Clifford,  L.  M.,  statement  of, 24 

Climate,  increase  of  the  gypsy  moth  retarded  by,       ....          5 

of  England,  influence  on  foliage, 271 

Clisiocampa  americana,         .        .     \  .     •   .        .        •:-..,>        •        •      402 
destroyed  by  Baltimore  oriole,      .......      213 

parasites  of .,...,        .        .        .        .      377 

Clisiocampa  disstria, .        .        .      402 

Coal  tar,  eggs  treated  with, 410 

use  of,  in  pruning, 177,  186 

Coccyzus  americanus.  1  ^  Cuckoo> 

erythrophthalmus.  J 

Cocoon,  formation  of, 332 

Codling  moth  taken  under  burlaps, 171 

Cogswell,  Hon.  Wm.,  resolution  introduced  into  Congress  by, .        .        83 
Colaptes  auratus.     See  Flicker. 

Cold,  effect  of ,  on  caterpillars, 96,328 

effect  of,  on  eggs, 294,  295 

Coleoptera,  predaceous,        .        .        .        • 381 

Collinson,  Mr.,  importation  of  the  gypsy  moth  into  England  by,      .      269 


Ixviii  THE   GYPSY  MOTH. 

PAGE 

Colonies  of  the  gypsy  moth,  age  of  new, 70,  80 

exterminated, 65,  70,  248 

found  in  woodland, 70,  85,  86,  107 

found  outside  of  region  infested  in  1891, 70 

isolated .        .  54 

isolated,  normal  rate  of  Increase  in, 95 

isolated,  spread  of, 97 

means  taken  to  find  new, 105 

resulting  from  traffic, 109 

Colony,  definition  of,    .        ...» 196 

Colors  of  gypsy  moth,  explanation  of, 272 

Colt,  W.  C.,  observations  on  the  flicker, 221 

Commission  appointed  by  Governor  Brackett 38 

appointment  of  second, 45 

first,  amount  expended  by, 73 

Metropolitan  Park,  hold  meeting  with  the  gypsy  moth  commis- 
sion,           78 

removal  of  first, 45 

report  area  of  infested  territory, 39 

second,  amount  expended  by  the, 73 

Commissions,  consultation  of  first  and  second 45 

Commissioners,  second,  receive  no  remuneration,      ....  45 

Committee,  agricultural,  hearing  held  by, 84 

agricultural,  Medf ord  visited  by, 36 

on  gypsy  moth,  appointment  of, 49 

entomological  adviser  appointed  to, 67 

information  concerning  the  gypsy  moth  in  Europe  obtained  by,  67 

members  of,  elected, 76 

name  of,  changed, 76 

organization  of, 49 

plans  of,  presented  to  legislature, 66 

report  of,  on  the  inspection  of  towns  bordering  infested  region,  65 

report  of  Professor  Fernald  and  the  director  to,          ...  C9 

work  of, 49 

Common  names  of  the  gypsy  moth 256 

Comparative  effects  of  different  arsenical  poisons,      ....  473 

Comstock,  Prof.  J.  H.,  infested  region  visited  by,      ....  79 
report  of  (Appendix  E). 

Condition  of  infested  region  in  1891 ."*      .  53 

Conference  at  office  of  State  Board  of  Agriculture  (Appendix  A),    .  45 

Congress,  efforts  to  secure  an  appropriation  from,      ....  83 

resolve  asking  for  aid  sent  to, 68 

Connell,  Mrs.  Margaret,  statement  of, 23 

Consumption  of  food  by  gypsy  moth  caterpillars,      .        .        .        .  315 

Contact  insecticides,    .        .        .        .        ....   57,58,163,485 

Contopus  virens.    See  Wood  pewee. 

Cook,  Prof.  A.  J.,  experiments  with  Paris  green,       .        .        .        .  162 

Corea,  gypsy  moth  from,      .        .•....-..        .338 

Cork  oaks  attacked  by  the  gypsy  moth, 274 

Corrosive  sublimate,  eggs  treated  with, 409 

Corvus  americanus.     See  Crow. 


INDEX.  Ixix 


PAGE 

Cotton  as  a  food  plant, 324 

trees  banded  with, 127,  128 

Cotton,  John,  statement  of,         .        .        .        ...        .        .        .  27, 44 

Coxe,  Wm.,  on  tree  pruning, .178 

Craig,  W.  C.,  at  conference  on  gypsy  moth  (Appendix  A),        .        .        45 

statement  of 19,  27 

Creepers  attacking  the  gypsy  moth  in  Europe 209 

attracted  by  meat,         •        .        .....        .        .        .      229 

Cremaster,  use  of,        .        .        ..        .        .     •  •        .-       .        .      333 

Creosote  and  paint  tube, .        .        .124 

eggs  treated  with, 63,  123,  410 

for  destroying  caterpillars, .        .      126 

Cricket,  destruction  of  crops  by "...      206 

Crimea,  The,  ravages  of  the  gypsy  moth  in,       .....      279 

Crockford,  A.  W.,  statement  of, 27,30,42 

Cronin,  Mrs.  Margaret,  statement  of,         ......        23 

Crow  blackbird  attacking  the  gypsy  moth, 207 

Crowley,  John,  statement  of, 7,18,29 

Crows  attacking  the  gypsy  moth, 207,  217,  224 

attacking  the  gypsy  moth  in  Europe, 209 

attracted  by  meat, 229 

destroying  predaceous  insects ..241,  394 

distributing  the  gypsy  moth 237 

experiments  on  gypsy  moth  eggs  with, 239 

time  required  in  digestion  by, 204 

value  of, 204 

Cuckoo  as  an  insect  destroyer, 205 

attacking  the  gypsy  moth,  •  .        .        .        .6,  207,  211,  212,  225,  227 

attacking1  the  gypsy  moth  in  Europe 208,211 

Currant  sawfly,  damage  from,     .        .        .        .        .        .        .        .270 

Curtis  on  occurrence  of  the  gypsy  moth  in  England,         .        .        .269 
Cutting  and  burning  infested  growth,         .        .        .        .39,  85,  164,  193 

Cyanide  of  potash  on  eggs 413 

Cyanides  as  insecticides, -     .        .  .485 

Cyanocitta  cristata.     See  Blue  jay. 

Cyclone  burner  for  destroying  the  gypsy  moth 121,  127 

nozzle, 150 

nozzle  used  for  burning, 120 

Cyrtoneura  stabulans .        .        .       387,  389 

D. 

Daly,  D.  W.,  statement  of, 9 

Damage  by  gypsy  moth  in  Old  World 273 

Danger  from  bad  pruning, 173 

from  freight  shipments, 110 

from  steady  traffic, 109 

Dasyllis  sacrator, 392 

Datana  ministra, 402 

Date  of  hatching  of  the  gypsy  moth, 294 

Daudeville  on  ravages  of  gypsy  moth  in  France,        ....  276 


Ixx  THE   GYPSY  MOTH. 


PAGE 


Davis,  Miss  R.  L.,  observations  on  molting 305 

De  Courval  on  tree  pruning, 178 

Defoliation  of  trees, 8-28,  85,  86,  273-284 

Dendrolene,  description  of, 135 

Dermestes  ater, 385 

lardarius, 384,  385 

Des  Cars  on  tree  pruning, 179,  186 

Destruction  of  birds,  folly  of, 205 

of  caterpillars, 58,69,87,126,165 

of  egg-clusters.      See  Egg  cluster. 

of  gypsy  moth,  methods  for, 117 

of  pupa3  and  moths, 194 

Destructiveness  of  the  gypsy  moth,     .         .  .23,  40,  57,  273-284 

of  introduced  insects, 250 

Dexter  elm,  the, 247 

Digestion  of  birds, 204 

of  eggs  of  the  gypsy  moth  by  birds, 239 

Digestive  system  of  gypsy  moth, 369 

Diglochis  omnivorus, 375 

Dimorphism,  sexual,  of  gypsy  moth, 272 

Dill,  J.  P.,  statement  of 16,26 

Dionychopus  niveus, 341 

Diptera,  predaceous .        .         .392 

Dipterous  parasites, .        336,  376,  385 

how  reared, 386 

Dei,  Apelle,  on  ravages  of  gypsy  moth  in  Europe,     ....      2-79 
Director  of  field  work,  inspection  of  infested  region  by,  ...        46 

visit  to  Washington  by,         .  83 

recommendations  of  entomologists  considered  by,  .        .        69 

report  of,  to  committee, 69 

visit  to  Amherst  by, 46 

Description  of  different  stages  of  the  gypsy  moth,      .        288,  300,  333,  336 

of  dipterous  parasites, 387 

Disease  among  caterpillars 280,  405 

Distance  females  can  assemble  males, 240,  351 

travelled  by  caterpillars,        .        .        .        .        .  .        .310 

Distribution  of  the  gypsy  moth, 94 

affected  by  extermination,     .        ... 113 

affected  by  food  supply,         .        ...        .        .        .        .        .95,97 

affected  by  natural  causes, 97 

a  study  of  methods  and  routes, 106 

as  caterpillars, 98 

as  eggs, 98,  103,  239 

by  animals, 103 

by  birds, 98,215,231,235,239 

by  man, 99,  100,  103,  106,  278 

by  traffic, 102-105,  109, 345 

by  travelling  of  caterpillars, 310 

by  wind 98,  278,  301 

compared  with  that  of  other  insects, 97 

in  other  countries, 267 


INDEX.  Ixxi 


PAOE 

Distribution  of  the  gypsy  moth,  peculiarities  of,        .        .        .        .  98,  99 

period  of  greatest, 104 

primary, 104 

relation  of  population  to,       .         ....        .        .        .        99 

results  of  study  of  methods, 107 

secondary, 104 

District  infested  by  gypsy  moth.     See  Infested  region. 

Dohrn,  Dr.,  on  parthenogenesis, 366 

on  vitality  of  larvae, •     .        .        .        .      278 

Donitz  on  singing  Lepidopteron, 341 

Donovan  on  occurrence  of  gypsy  moth  in  England,  • .         .        .        .268 

Douglass  and  Scott  on  breeding  Heteroptera, 394 

Dovvd,  Mrs.  John,  statement  of, 22 

Downy  woodpecker  attacking  the  gypsy  moth,   ....       207,  221 

Drassus  sp.  attacking  the  gypsy  moth, 405 

Drew,  C.  It.,  statement  of,  .........        59 

Dryobates  pubescens.     See  Downy  woodpecker. 
villosus.     See  Hairy  woodpecker. 

Dryocampa  rubicunda, 402 

Dubois  on  ravages  of  the  gypsy  moth  in  Belgium,      .        .        .        .279 

E. 

Ebermayer,  Dr.,  on  birds  v.  the  gypsy  moth, 209 

Eck  raupenleim  machine, 133 

Effects,  injurious,  of  arsenic  (Appendix  F),        ....       161,162 

of  extermination  on  distribution, 113 

of  insecticides  on  foliage 159,  489 

Egg-clusters  of  the  gypsy  moth,  advantage  of  destruction  of,  84,  117,  284 

age  of,  how  determined, 95 

comparison  of  number  destroyed  annually, 93 

destruction  of, 63,  117 

destruction  of,  in  Europe, 284 

distribution  of,  by  streams, 98 

how  laid 363 

number  of  caterpillars  from,          .        .        .        .        .        .         94,  297 

number  destroyed  in  1891,     .        .        .  ^    .        .        .        .         .        54 

of  unfertilized  females,         .        .        .  '    .        .        .        .       290,  367 

old  distinguished  from  new, .        .        ....        .        .        95 

size  of • 289 

treated  with  acids,         .        .        .      •'.'      .        .          63,123,413,415 
treated  with  creosote,    .        .        .        .        .        .»        .         63,123,410 

where  found, 98,  126,  289 

Egg-feeding  birds,  value  of,         .        .         .        .        .    *    . "      .        .      229 

Egg-gathering  and  fall  inspection,       .        .        ...        .        .        60 

Eggs  of  the  gypsy  moth,  birds  which  may  eat,   .        .        .        .       228,  229 

burning  of, 57,119,284 

danger  from  transportation  of ,     .        .        .        .        .        .        .       Ill 

description  of,        .        .        ....        .        .        .        .288 

destruction  of,        ...        .       85,  39,  53,  63,  69,  78,  84,  125,  195 

distributed  by  birds,      .       -.'        .         .        .         .        .        .       230,239 


Ixxii  THE   GYPSY   MOTH. 


PAGE 

Eggs  of  the  gypsy  moth,  effects  of  digestive  processes  of  birds  npon,      239 
effects  of  extremes  of  temperature  on,  .        ...  .292 

experiments  with  insecticides  on, 407 

hatching  of,  how  accomplished, 297 

how  covered, 289 

implements  used  in  search  for, 125 

number  of,  deposited, 94,  289 

number  of,  in  female, 364 

number  of,  laid  by  poorly  fed  females, 95 

of  dipterous  parasites,  .        .  .        .        .        .        .        .      385 

removed  by  dissection,  .        .        .        .        r  .        .      364 

scattering  of, 117,239,290,363 

time  required  for  fertilization 343 

vitality  of, 279,  291 

Eichoru  raupenleim  machine, 131 

Elachiptera  dispar, 390 

Electric  insecticide 482 

Elm,  the  Dexter, 247 

trees  attacked  by  Chrysomela  scalaris, 235 

Elms  attacked  by  gypsy  moth, •  277 

"Elphona," 483 

Embryo,  development  of,     .        .         .        .        .        .        .        288,  294,  295 

Emerging,  process  of, ^        .        .      336 

Emerton,  J.  H.,  spiders  identified  by, .        .        .        .      ••        .        .      404 

Empidonax  minimus 207 

Employees,  number  of,  yearly, .  89-91 

uniform  of, .        .        .        .        .       114 

Emulsion,  kerosene,  use  of, 163,  485 

Enemies,  natural.     See  Natural  enemies. 

England,  extermination  of  gypsy  moth  in,  .        .        •  ^    .        .        .      269 

occurrence  of  gypsy  moth  in, 267,  268 

English  sparrow  attacking  the  gypsy  moth,        .        .        .        208,231,234 
Importation  of,  into  America,        .        .        .        .        .        .       233,  234 

Eutachina  larvarum, 392 

Entomological  adviser,  Prof.  C.  H.  Fernald  appointed,     ...        57 
opinion  of,  in  regard  to  extermination,         .....        67 

Entomologists,  recommendations  of,  . 69 

conference  of,         . 45 

infested  region  inspected  by 69,79 

reports  of  (Appendices  D  and  E). 

spraying  recommended  by 45 

Enwright,  Wra.  J.,  statement  of, 40 

Epeira  strix, 405 

Epiblemum  scenicum 405 

Escape  of  the  gypsy  moth,  statements  in  regard  to 4 

Essex  County  Agricultural  Society,  petition  presented  by,         .         .        36 

Eupelmus  bifasciatus,    . 377 

Europe,  distribution  of  gypsy  moth  in, 267 

methods  of  destroying  the  gypsy  moth  in,    .  117,284 

European  birds  attacking  gypsy  moth  eggs, 231 

birds,  introduction  of, 232 


INDEX.  Ixxiii 

PAGE 

European  dipterous  parasites, 392 

food  plants 325 

hymenopterous  parasites, 377 

methods  for  destroying  the  gypsy  moth, 284 

predaceous  beetles, 385 

Eurytoma  abrotani,       .        .        .        .        .        .        *        .        .        •      377 

Everett,  petition  presented  by  selectmen  of, 36 

Eversman,  Professor,  on  ravages  of  gypsy  moth  in  Orenboorg,         .      280 
Examination  of  stomachs  of  various  birds,         .        .        .       212,215,231 

of  stomach  of  toad, 405 

Excresences  from  bad  pruning,    .        .         .        .        .        .        .        .177 

Exhibit  at  Atlanta  Exposition, .        .201 

at  Mechanics  Fair,         .....        .        .        ...        .        .      201 

at  World's  Columbian  Exposition,        .         .         .        .        .        .      200 

Exorista  sp.,  parasitic,  on  gypsy  moth  in  America  and  Europe, .       387,  392 

Experiment  station, .        .         .         87,  406 

Experiments,  amount  of  food  consumed,    .        .        .        .     -  .        .315 

assembling, ,  345 

birds  v.  gypsy  moth  eggs, 229 

cotton  as  a  food  plant, .        .324 

destruction  of  eggs, 122 

distance  travelled  by  caterpillars,          ......      310 

effects  of  light  on  caterpillars, _.        .      310 

extremes  of  heat  and  cold  on  caterpillars,    .        .        .        .        .      327 

extremes  of  heat  and  cold  on  eggs 292 

fertilization  of  female  moths, .343 

food  plants, 316 

food  selection, .485 

insecticide .      55,  69,  87,  407,  417,  477 

insecticides  on  foliage, 489 

parthenogenesis, 365 

trapping  caterpillars, 311 

trapping  male  moths, .        .      357 

Exterminated  colonies,         .        .        .        .        .  .        .         70,248 

Extermination,  advice  of  State  Board  of  Agriculture  concerning,      .        70 

aid  given  by  birds, 238 

by  burlapping  and  hand  killing, 64 

circumstances  favoring, 244 

effect  on  distribution 113 

how  accomplished,         . 127 

in  orchards, 248 

in  outer  towns, 115 

in  woodland, 88,  248 

local  success  of, 247 

measures  urged  to  provide  for, 35 

obstacles  to, 245 

opinions  of  entomologist  in  regard  to, 67 

progress  of .        .        .244 

results  of  efforts  toward, 70 

spraying  not  successful  as  a  means  of,  .  .  .  .56,  62,  138 
Exterminative  measures,  numbers  of  caterpillars  reduced  by,  .  .  60 
External  anatomy  of  moth, 339 


Ixxiv  THE   GYPSY  MOTH. 

F. 

PAGE 

Fall  hatching, 295 

False  alarms,  places  from  which  received, 201 

Farlow,  Dr.,  on  vegetable  parasites, 405 

Farmers,  distribution  of  moth  by 109 

methods  most  useful  for, .        .  194 

Feeding  habits  of  gypsy  moth, 311 

time  of, 311 

Fells,  Middlesex,  colonies  of  the  gypsy  moth  found  in,       .         .        .  86 

condition  of 87 

control  of  by  Metropolitan  Park  Commission,      ....  78 

Felt,  E.  P.,  experimental  work  by, 57 

observations  on  chipping  sparrow, 215 

observations  on  Dermestes  lardarius 384 

on  whale-oil  soap, .  163 

on  mites, 404 

Female  gypsy  moth,  abdomen,  hair  of 342 

anatomy  of, 339 

attacked  by  ants, 380 

attraction  of  males  by 240 

birds  feeding  on, 217,  228 

description  of, 337 

distribution  of,  by  birds, 239 

does  not  fly, 97,  112,  344 

eggs  laid  by  infertile, 365 

eggs  removed  by  dissection  of, 364 

eggs  scattered  by, 290 

lack  of  fat  in, s* 373 

length  of  life, .        .       343,  362 

mating  of, 342 

number  of  eggs  deposited  by,         .        .        .        .        .         .         .94,95 

polygamous,  . .343 

reproductive  system  of 375 

unfertilized,  eggs  laid  by, 290 

Fences,  comparison  of  yearly  work  on 93 

Fenton,  Mrs.  M.  F.,  statement  of,       .        .        .        ...      9,  30,  42 

Fernald,   Dr.  H.  T.,  report  of  (Appendix  D). 

Fernald,  Mrs.  C.  H.,  identification  of  gypsy  moth  by,        ...  32 

Fernald,  Prof.  C.  H.,  advice  concerning  egg  killing, .         .         .        .  119 

advice  concerning  field  work,        .....        .        .        .  57 

appointed  entomological  adviser, .  57 

at  conference  on  gypsy  moth  (Appendix  A). 

consultation  with, 46 

experiments  by, 142 

field  work  examined  by, 34,  57 

invitation  to  entomologists  to  visit  infested  region,     ...  69 

recommendations  of  entomologists  considered  by,      ...  69 

recommendation  of  policy  of  State  work, 251 

record  of  introduction  of  gypsy  moth, 3 

report  of,  to  committee, 69 


INDEX.  Ixxv 


PAGE 

Fertility  of  scattered  eggs, 291 

Fertilization,  time  required, 343 

Fertilized  females,  assembling  by, 363 

Field  force  discharged, .        .        .        .  63,  84 

organization  of,  .        .        .  .        .        .        .        .        50 

reductions  of ,         .         ....        ;        .        .:       .        .60,64,79 

operations  criticised  by  Professor  Riley, 56 

pupation  of  the  gypsy  moth  in  the, 335 

work  begun,  .         .        ..... 47 

work,  discontinuance  of,       .....        .        .     68,  78, 84 

Fifleld,  Mrs.  George,  on  migration  of  caterpillars,      ....         13 

Fifleld,  W.  W.,  statement  of, 21,  44 

Fingerling,  Prof .  Max  on  egg  killing,          .        .        .        .        .        .       118 

Fire,  aid  furnished  by,          .        .        .        .        ...        .        .  7,  166 

caterpillars  destroyed  by, 58,  59,  87,  126 

eggs  destroyed  by, 57,118,119 

numbers  of  moths  destroyed  by, 92 

Fires,  rules  concerning  (Appendix  B). 

First  destructive  appearance  of  the  gypsy  moth,        ....          7 

Fish-oil  soap,  use  of, 163 

Fitchburg  Railroad,  inspection  of, Ill 

Flicker  attacking  the  gypsy  moth, 221,227 

Flight  habits  of  gypsy  moth, 97,  112,  342,  344 

Flinn,  Mrs.  J.  W.,  statement  of, 8,  22,  25,  27 

Flood,  M.  J.,  observations  on  blue- jay,       .        .        .        ..  .214 

Fly-catchers  attacking  the  gypsy  moth,       .         .     7,  207,  219,  226,  227,  236 

Foliage,  area  of,  on  trees, 494 

destruction  of,  by  caterpillars,      .        .        .      8-28,  59,  85,  96, 273-284 

effect  of  insecticides  on, 159,  489,  494 

Follansbee,  Mrs.  S.  J.,  statement  of,  .        .         .        .        .        .        .  17,  27 

Food,  amount  consumed  by  caterpillars, 315 

amount  necessary  for  birds, ........      204 

distribution  of  the  gypsy  moth  from  lack  of,  95 

existence  of  caterpillars  without,  .        .        .  •  .       ..-        .      325 

plants  of  the  canker  worm,    .        .        .        .•       .        .        .        .        97 

plants  of  the  gypsy  moth,      .        ...        .'      .        .         68,246,316 

plants  of  the  gypsy  moth,  cotton  as,    .        •.....»        .        .        .      324 

plants  of  the  gypsy  moth  in  Europe,     .        ...        .        .        .325 

plants  of  the  tent  caterpillar, 97 

selection  by  gypsy  moth  caterpillars,    ......      485 

Forbush,  E.  H.,  director,  lectures  on  gypsy  moth  by,         .        .         .      200 

on  colors  of  animals  of  British  Columbia, 271 

on  feeding  habits  of  crows, 394 

report  on  birds  v.  gypsy  moth, 203-243 

suggestions  concerning  caterpillar  traps  by,         .        .         .        .311 
Force,  field.     See  Field  fofce. 

Forests  attacked  by  gypsy  moth, 97,  274 

possible  danger  to,  from  gypsy  moth, 70,  87 

Formica  subsericea, 381 

Foster,  F.  E.,  statement  of, 18,29 

Fowls  affected  by  arsenic, 162 


Ixxvi  THE   GYPSY  MOTH. 


PAGE 

Fowls  feeding  on  gypsy  moth  caterpillars, 222 

France,  ravages  of  the  gypsy  moth  in,        ....         274-276,  283 
Fraxinus  excelsior,  exempt  from  ravages  of  gypsy  moth,  .         .        .282 

Freezing  mixtures, 293 

French,  J.  N.,  statement  of, 27,30,31 

Frisch,  J.  L.,  on  injuries  by  gypsy  moth, 274 

Frost,  H.  L.,  on  food  plants  of  the  gypsy  moth,         ....      316 

on  predaceous  bugs 395 

Fruit  crop  increased  by  spraying,        .        .        ....        .         .        60 

loss  of,  .        .        .        •        . 26,  41 

poisoned  by  spraying 161 

trees  in  Europe  attacked  by  gypsy  moth, 271 

trees  how  sprayed, 158 

Fiirst,  Hermann,  quoted  on  birds  attacking  caterpillars,    .        .         .      208 

G. 

Galeruca  xanthomeloena,  increase  of,  due  to  sparrows,        .         .        .      235 

Garden  crops  destroyed 26 

Gases  for  destroying  eggs, 125 

Gaurax  anchora, 387 

Gazen  on  ravages  of  gypsy  moth  in  Kirsanov, 282 

Genitalia,  description  of, .        .339 

Germany,  ravages  of  the  gypsy  moth  in, 274 

Gerstiicker,  Dr.,  on  the  killing  of  trees  by  gypsy  moth,      .        .         .277 

Gibson,  R.,  statement  of, 20 

Glands,  accessory,  of  gypsy  moth, 375 

Glass,  binocular,  use  of, 125 

Glover,  Townend,  on  insectivorous  birds,  ......       207 

Glucose,  use  of , J  ..        .     -    65,142 

Godart,  on  injuries  by  gypsy  moth 275 

Goodell,  Pres.  H.  H.,  aid  of,  in  securing  assistants,  4G 

letter  to  Governor-elect  Brackett  by,    .        .        .        ...        35 

Goodwin,  F.  M.,  statement  of, 12,19 

Goodwin,  3.  O.,  description  of  movements  of  gypsy  moth  caterpil- 
lars,         ...'.. 13 

statement  of ,.        .        ....        .        .        .        .         .        .21,31 

Gordon,  Miss  Carrie,  observations  on  molting, 304 

Gould,  L.  S.,  at  conference  on  gypsy  moth  (Appendix  A),         .        .        45 

Gould  pumps, 150 

Grackle,  purple,  attacking  the  gypsy  moth, 207 

Graeser  on  distribution  of  gypsy  moth, 267 

Graff,  V.  E.,  on  ravages  of  gypsy  moth  in  Riazan,     ....      281 

Grafting  wax,  use  of,  in  pruning  trees, 177 

Grain  attacked  by  gypsy  moth  in  Europe, 283 

Grass  eaten  by  gypsy  moth  caterpillars, 68,282 

Great-crested  flycatcher  attacking  gypsy  moth  caterpillars,        .        .       207 

Great  titmouse  attacking  other  birds, 233 

Green,  I.  C.,  observations  on  the  redstart, 219 

Green,  Paris.     See  Paris  green. 

Grimm  on  feeding  habits  of  birds, 208,  222 


INDEX.  Ixxvii 

PAGE 

Grosbeak,  rose-breasted,  attacking  gypsy  moth,         .        .        .       207,  219 
Grote,  Prof.  A.  R. ,  on  systematic  position  of  dispar,         .        .        .      256 

Gulls  as  insect  destroyers, 206 

Gypsy  moth,  acclimation  of, 94 

act  to  provide  against  depredations  by, 47 

annual  increase  of,          .         .        . 95 

area  occupied  by, .        .        .         94,  103 

attacked  by  parasites,     .         .        .        .        .        .        .        .       375,385 

attacked  by  predaceous  insects, 381,  392 

bibliography  of 257 

caterpillars.     See  Caterpillars  of  the  gypsy  moth. 

colonies  of,  exterminated,      .        .  x    .        ...        .        .        65 

committee,  appointment  of,  ........        49 

committee,  meeting  of,  with  Metropolitan  Park  Commission,     .        78 

committee,  name  of,  changed 76 

comparison  of  numbers  destroyed  yearly, 93 

common  names  of, 256 

conditions  favoring  rapid  increase  of, 95 

description  of  caterpillar, 300 

description  of  eggs, 288 

description  of  imago, 336 

description  of  pupa 333 

destruction  of,  by  birds 7,  96,  209,  272 

destruction  of,  by  burlapping, 167 

destruction  of ,  by  burning, 119,127 

destruction  of,  by  spraying, 58 

destructiveness  of 23,  40,  57,  70 

distribution  of.     See  Distribution. 

efforts  of  citizens  to  destroy, 34,  68,  77,  84 

egg-clusters.     See  Egg-clusters. 

exterminative  methods  to  reduce  number  of,        ....        60 

female.     See  Female. 

first  destructive  appearance  of, 7 

food  plants  of »  •      .        .        .  58,  97,  318 

form  in  which  imported,        .        .        •        .      •«        .        .        .          4 

hermaphrodites, 339 

hibernation  of, 245 

history  in  America 3 

history  in  the  Old  World 273 

identification  of, 32 

in  America,  occurrence  of,  recorded  by  Professor  Riley,      .        .          3 

in  England, 268 

in  England,  how  exterminated, 272 

in  Europe, 67,  274 

in  Europe,  methods  for  destroying, 284 

increase  of,  checked, 94 

increase  of,  due  to  English  sparrow, 235 

increase  of,  retarded  by  fires, 7 

increase  of,  retarded  by  isolation, 6 

injuries  of,  in  Old  World 273 

injuries  of,  to  woodland,        . 88 


Ixxviii  THE   GYPSY  MOTH. 


Gypsy  moth,  introduction  of  into  America  by  Leopold  Trouvelot,     .          3 
introduction  of,  recorded  by  Professor  Fernald, ....          3 

Japanese,  size  of, 338 

males.     See  Male  moth. 

means  of  preventing  spread  of,  caterpillars,         ....        63 

means  taken  to  find  new  colonies, 105 

migration  of,  in  search  of  food, 13,  97 

natural  enemies  of,        .        .  :  .        .        .        .6, 95,  203,  375 

number  of,  colonies  exterminated,        .        .        .        .        .        .        70 

number  of,  destroyed  by  fire,        .        , 92 

number  of,  destroyed  by  spraying, 92 

number  of  eggs  deposited  by, 94 

numbers  of,  in  populated  districts, 99 

origin  of  isolated  colonies, 103 

outbreak  of,  in  1889, 10 

parasites  of, 57,  96,  375,  385 

peculiarities  of  the  distribution  of, 98,  99 

period  of  greatest  distribution, 104 

plants  destroyed  by  the, 70,  318 

possible  spread  of, 250 

pupae.     See  Pupje. 

rapid  development  of, 86 

ratio  of  increase  of, 95 

ravages  of,  first  noticed, 32 

result  of  the  transportation  of, 102 

seasons  favorable  for  the  increase  of, 95,  96 

second  brood  of, 86,  295 

secondary  distribution  of,      .        .        .        .        .        .        .        .104 

spread  of,  compared  with  that  of  canker  worm, ....        97 

statements  from  citizens  concerning  escape  of,   ....          4 

study  of  the  distribution  of ,          .        .      -.        .        .        .        .        94 

swarming  of  the  male,  .         .        .        ...        .        .  86 

systematic  position  of ,  .         .        .     '  .        .        .        .        .        .       256 

v.  English  sparrow, 234 

weather  favorable  for  the  increase  of,          .        . "       .        .        .        84 

H. 

Habia  ludoviciana,        .        .        .        .        ...        .        .        .207 

Habits,  feeding,  of  gypsy  moth  caterpillars, 311 

of  flight  of  gypsy  moth, 344 

of  the  gypsy  moth,  observations  on  the, 87 

spinning,  of  gypsy  moth  caterpillars,   ....        279,  330,  332 
Hair  deposited  by  the  gypsy  moth  in  laying,        ....       342,  3(54 

Hairs,  aerostatic,  of  caterpillars 301 

Hairy  caterpillars,  immunity  of,  from  birds 208,  210 

covering  of  nests, 289 

woodpecker  attacking  the  gypsy  moth,        .         .        .        .       207,  221 

Hamlin,  Mrs.  I.  W.,  statement  of, 11,  20,  30 

Hand-killing  of  caterpillars,  efficiency  of, 64 

Harlow,  J.  W.,  statement  of, 25,  28 


IXDEX.  Ixxix 

PAGE 

Harmon,  Wm.  B.,  statement  of 26,30,41 

Harpalus  caliginosus, 382,  385 

pennsylvanicus 382,  384 

Harris,  Dr.  T.  W.,  on  occurrence  of  gypsy  moth  in  England,    .         .      268 

on  use  of  burlap, 171 

Hartig,  Dr.  R.,  on  raupenleim,     .         .        .-.-..        .         .130 

on  tree  pruning,     .        .        .        .-..-.        .        .         .       180 

infested  region  visited  by,      .        .        .        .        .        .        .        .        79 

Harvey,  Prof.  F.  L.,  report  of  (Appendix  E). 

Hatch  Experiment  Station  Bulletin,  introduction  of  gypsy  moth  re- 
corded in,        ..........          3 

Hatching  of  gypsy  moth  caterpillars,  date  of,  .        .        .        .       294 

fall, .        .        .        .        .295 

Hauenstein  raupenleim  machine,          .        .        .        ....         .       133 

Haushalter,  F.  H.,  statement  of, •     .         .        21 

Haworth  on  occurrence  of  gypsy  moth  in  England,   ....       268 
Heat,  effect  of,  on  gypsy  moth  caterpillars, 327 

effect  of,  on  gypsy  moth  eggs, 119,  293 

fall  hatching  produced  by,     .        . 296 

Hermaphrodites,  gypsy  moth 339 

Hemiptera,  predaceous,      •"«-.• 392 

Hemitcles  fulvipes, ;  378 

Henry,  Professor,  on  egg-killing,         .        .        .        .  .         .118 

on  ravages  of  the  gypsy  moth  in  France, 283 

Henshaw,  Samuel,  appointed  entomologist  to  first  commission,         .         38 

on  enemies  of  gypsy  moth, 405 

Hericart,  F.,  Viscount,  on  ravages  of  gypsy  moth 276 

Hess,  Dr.  Richard,  on  means  of  destroying  the  gypsy  moth,      .         .      285 
Hibernation  of  the  gypsy  moth,  .        .         .        .  .        .        .       245 

of  parasites, • .      ••  .        .        .        .      377 

of  predaceous  bugs, 403 

Highways,  caterpillars  of  gypsy  moth  found  along,    ....        99 

inspection  of,          .        .         .  .  .        .        .197 

History  of  gypsy  moth  in  America,      .         .         .        .'-...         .  3 

of  gypsy  moth  in  the  Old  World, 273 

Hochleim  raupenleim  machine,     .        .        .        .        .        .        .        .       132 

Hofmann,  Dr.,  on  disease  of  nun  moth, 405 

Holland,  occurrence  of  gypsy  moth  in, 268,  283 

Homeyer  on  distribution  of  gypsy  moth, 267 

Hornets,  predaceous, 378 

Hose,  Eck  raupenleim, 133 

for  spraying » 147 

House  swallows  driven  away  by  sparrows, 234 

House  wren  attacking  the  gypsy  moth, 208,227 

Howard,  L.  O.,  opinions  of,  on  gypsy  moth  work  (Appendix  E). 

Hutching,  John,  statement  of, 43 

Hyannis  tobacco  mixture  as  insecticide, 483 

Hydrochloric  acid  on  eggs, 413 

Hydrocyanic  acid  gas,  eggs  treated  with, 410 

Hydrogen  arsenide,  eggs  treated  with, 412 

sulphide,  eggs  treated  with,  ........      412 


Ixxx  THE   GYPSY   MOTH. 


PAGE 

Hylan,  J.  P.,  on  assembling  of  gypsy  moth, 345 

on  leaf  area  of  trees, 495 

Hylapickeringii, 404 

Hymenoptera  attacking  the  gypsy  moth, 375 

Hymenopterous  parasites  destroyed  by  flycatchers,    .        .        220,  241,  376 

Hyphantria  cunea, 402 

Hypogymna  dispar,        ••        .        .        .        .        .        .        .        .        .  255 


I. 

Ichneumon  disparts, 378 

grandis,  hibernation  of, 377 

Ichneumons  captured  by  birds, 220,241,376 

Icterus  galbula.        See  Baltimore  oriole. 

Imago  of  gypsy  moth.     See  Female  moth ;  male  moth. 

Implements  used  in  searching  for  eggs, 125 

Importation  of  birds, 232 

of  English  sparrow, 233,  234 

of  gypsy  moth,  form  of, 4 

of  parasites, 288,  406 

Imported  insects,  damage  from, 270 

In-and-in  breeding, 368 

Increase  of  the  gypsy  moth, 94 

conditions  favoring  rapid, 95 

due  in  some  measure  to  sparrows, 235 

influences  that  retarded, 5 

normal  rate  of,  in  isolated  colonies 95 

on  neglected  lands, 31 

ratio  of, 95 

retarded  by  climate 5 

retarded  by  isolation,     .........          6 

weather  favorable  for  the, 84 

Indigo  bird  attacking  gypsy  moth, 207,  219 

Infestation,  centres  of, 104 

Infested  estates,  account  kept  of, 52 

localities,  birds  frequenting, .223 

localities  designated  on  maps,       .        .        .         ...        .        .  50,  52 

region  appointed  to  inspectors,     .......        49 

region,  colonies  found  in  1891  outside  of, 70 

region,  condition  in  1891, 53 

region,  description  of,  .        .         .        .  .'  .       100,101 

region,  extent  of, 53,  108 

region,  how  inspected, 196 

region,  inspection  of  belt  around, 108 

region  of  1891,  moth  rarely  found  outside  of 61 

region,  proportion  of  population  in, 101 

region,  railroads  running  through 101 

region  visited  by  Agricultural  committee, 36 

region  visited  by  entomologists, 69,  79 

towns,  proportionate  numbers  of  the  gypsy  moth  in,  .         .         .        99 


INDEX.  Ixxxi 

PAGE 

Infested  woodlands, 116 

woodlands,  known  area  of, 87 

Information,  bulletin  of, 34,  200 

of  the  public,  measures  for, 34,  198,  200 

Injuries  by  gypsy  moth  in  Old  World,         .        .  (      .        .        .        .273 

severity  of, 58 

spread  of, 59 

to  man  aud  animals  from  spraying  (Appendix  F),       .        .        .       161 
to  woodland  by  the  gypsy  moth 85,  88,  273-284 

Ink,  printers'  used  in  destroying  the  gypsy  moth 34 

Insectary,  description  of, 406 

Insecticides,  contact, 57,  58,  163,  485 

danger  from  arsenical  (Appendix  F). 

experiments  with, .   55,  69,  407,  477 

for  destroying  caterpillars, 417,  477 

Insectivorous  vertebrates  (other  than  birds), 404 

Insect  lime.     See  Raupenleim. 

Insects,  birds  as  destroyers  of, 204 

imported,  danger  from, 270 

Inspection,  annual, 196 

force  insufficient  for, 79,81 

of  belt  around  infested  region, 106 

of  Boston,  result  of,    .          . .80 

of  outside  territory, 110,111 

of  outside  towns,  result  of 65,  70 

of  railroads, .       Ill 

of  wooded  region, 66,  87 

Inspections  of  1891 .        .         .52,60,99 

Inspectors,  observations  reported  by 51 

town-sections  allotted  to .        .        50 

Internal  anatomy  of  gypsy  moth, 368 

Introduction  of  English  sparrow, 233,  234 

of  European  birds, 232 

of  European  parasites,  .        .      \.        .        .       ".        .        .       288,406 
of  gypsy  moth  into  America  by  Leopold  Trouvelot,    ...          3 

of  gypsy  moth  into  England, 269 

of  gypsy  moth,  recorded  by  Professor  Fernald,  ....          3 

Investigating  committee,  appointment  of,  urged   by  gypsy  moth 

committee, 68,  77 

Isolated  colonies  of  the  gypsy  moth, 103 

injury  from, 95 

normal  rate  of  increase  in, 95 

Italy,  ravages  of  the  gypsy  moth  in, 279 

J. 

Jiiger,  Dr.,  on  diseases  of  nun  moth 405 

Japan,  occurrence  of  gypsy  moth  In, 267 

Japanese  gypsy  moth,  size  of, 338 

Jay,  blue,  attacking  the  gypsy  moth 6,  207,  225 

attracted  by  meat, 229 


Ixxxii  THE   GYPSY   MOTH. 


PAGE 

Jay,  blue,  destroying  predaceous  insects, 241 

distributing  the  gypsy  moth, 236 

feeding  habits  of, 210,  231 

Joly,  M.  N.,  on  ravages  of  the  gypsy  moth 276 

Jones,  F.  H.,  preparation  of  soap  powder  emulsion  by,      .        .        .       163 

K. 

Kazan,  ravages  of  the  gypsy  moth  in, 281,283 

Kearly,  George,  on  increase  of  insects  following   destruction   of 

birds 205 

on  scarcity  of  gypsy  moth  in  England, 269 

Kelly,  Mrs.  Daniel,  statement  of 22 

Keppen,  Theodore,  note  on  cuckoo, 208 

on  gypsy  moth  in  Russia 268,  280 

Kerosene  emulsion,  use  of 163,  485 

for  destroying  caterpillars 126 

for  destroying  eggs, 416 

Kharkov,  ravages  of  gypsy  moth  in, 281 

Kiev,  ravages  of  the  gypsy  moth  in, 281 

King  birds  attacking  the  gypsy  moth,          ....        207,  226,  227 

Kinglet  attracted  by  meat 229 

Kirby,  Catalogue  Lepidoptera  Heterocera, 255 

Kirkland,  A.  H.,  cages  for  breeding  beetles,        .        ...         .384 

observations  on  wood  pewee, 220 

on  assembling  of  gypsy  moth, 345 

on  fall  hatching, 296 

on  food  selection  by  larvae, 485 

on  garden  toad,      .        .        .        .  .        .        .        .404 

on  internal  anatomy  of  gypsy  moth, 368 

on  predaceous  Hemiptera,     .         .....        .  392 

on  leaf  area  of  trees,      .        .        .  .        .        .        .        .494 

Kirsanov,  ravages  of  gypsy  moth  in, 282 

Kishenev,  ravages  of  gypsy  moth  in, 280 

Klausen,  experiments  of,  with  wadding  bands 286 

Knapsack  pump,  . 149 

Knives,  cleaning,  .  •'"'..•        •        •        j        •        •        •        .126 

Kollar,  Vincent,  on  egg  killing,  .        . 118 

on  use  of  burlap,   .        .        .        ...       '..      .         .        .       171 

Kornauth,  Wachtl  and,  on  diseases  of  nun  moth,       ....       405 

Kulagin,  N.,  on  injuries  of  gypsy  moth  in  Russia,       ....       280 


L. 

Labodsky  on  bands  for  trees 285 

Lacy,  Sylvester,  statement  of, 17 

Larches  attacked  by  gypsy  moth, 277 

Larch  saw-fly,  damage  from 270 

Laria  dispar, 255 

Larvae  of  gypsy  moth.     See  Caterpillars  of  gypsy  moth. 


INDEX.  Ixxxiii 

PAGE 

Law  for  protection  of  birds,  need  of  enforcement  of,         .        .        .       242 

Lawrence,  Gen.  S.  C.,  testimony  of, 10 

Lawrence,  Mrs.  C.  A.,  statement  of, 29 

Lead,  arsenate  of.     See  Arsenate  of  lead. 

Leaf  area  of  trees, 494 

Least  flycatcher  attacking  the  gypsy  moth, 207 

Leaves,  how  injured  by  arsenical  poisons,  ...        .        .        .      494 

Legislature,  petition  for  extermination  of  gypsy  moth  presented  to,        36 
Length  of  life  of  imago .       343,362 

larvae  without  food,       .        .        .        .        .        .        .        .       278,  325 

Lepidoptera  attacked  by  predaceous  bugs,  .        .        .        .        .        .393 

Lepidopteron,  singing,         .        .        . 341 

Lettuce,  quantity  eaten  by  gypsy  moth,       ......      315 

Lexington,  area  of  woodland  infested  in, 87 

Light,  caterpillars  attracted  to,    .        .        .  .        .        .        .      310 

Limbs,  large,  removal  of, 184 

Lime,  insect.     See  Raupenleim. 

Limenitis  ursula,  .....        .        .        .        .        •    "    .        .         .      402 

Lindens  attacked  by  gypsy  moth,         . 274 

Lines  of  travel,  relation  of  distribution  to,         .        ...        .       108 
Lintner,  Dr.  J.  A.,  infested  region  visited  by, 69 

report  of  (Appendix  D), 

Liparis  dispar,        ...        .        .        .     • 255 

monacha,  damage  by, 130 

use  of  raupenleim  against, 132 

Literature  on  gypsy  moth, 257-267 

Lithobiusforjicatus,       .        .        ....  ."      .        .        .405 

Livonia,  occurrence  of  gypsy  moth  in,         .        .        .        .        .       267,268 

Local  extermination,  success  of,          .        .        ...        .        .        .      247 

Localities,  infested,  birds  frequenting, 223 

Locusts  destroyed  by  birds, 205 

Lodi  on  vitality  of  caterpillars, .327 

Loeffler,  E.,  statement  of, 42 

London  purple,     .        .        .    "    .      .  i,        .        .        .        .        140,  417, 477 
Leech,  J.  H.,  on  Japanese  gypsy  moth,        .        .       •.        .        .        .      338 

Lycosa  sp.  attacking  the  gypsy  moth, 405 

Lymantria  monacha,  aerostatic  hairs  of, 301 

disease  of, 405 

M. 

Macharcea  serriventris, 392 

Machines  for  burning  eggs, 119 

raupenleim, 131 

spraying, 149-156 

Majorca,  island  of,  occurrence  of  gypsy  moth  in,       ....  267 

Maiden,  office  removed  to, 55 

petition  presented  by  city  officials  of, 36 

trees  defoliated  by  gypsy  moth  in, 57 

Male  gypsy  moth,  anatomy  of, 339 

attracted  by  pupae, 363 


Ixxxiv  THE   GYPSY   MOTH. 


PAGE 

Male  gypsy  moth,  birds  feeding  on, 228-240 

description  of 336 

digestive  system  of, .        .        .371. 

distance  over  which  female  attracts, 240,  351 

experiments  in  trapping, 69,  357 

flight  of 344,  345 

length  of  life  of, 343 

mating  of,       .        .        ,        .        .        .        .        .        ...      342 

polygamous, 343 

presence  of  fat  in, 373 

reproductive  system  of 373 

Malpighian  vessels  of  gypsy  moth,  structure  of,         ....      370 

Man,  distribution  of  the  gypsy  moth  by, 99,  100-103 

Maps,  section 50 

Market  gardeners,  distribution  of  moth  by 109 

Marptusafamiliaris, 405 

Martin,  Dr.  Pearl,  appointed  commissioner, 38 

Martins  driven  away  by  sparrows, 234 

Maryland  yellow-throated  warbler  attacking  the  gypsy  moth,    .         .       208 
Massachusetts  Agricultural  College,  students  of,  as  assistants,          .        46 

Horticultural  Society,  action  of, 36 

Mating  of  gypsy  moth, 342 

Maynard,  C.  J.,  note  on  bird  digestion, 204 

Maynard,  Prof.  S.  T.,  recommendation  concerning  painting  trees,    .       178 
Mayo,  Mrs.  Thomas  F.,  statement  of,          .        .         .        .        .     15,22,24 

McCarty,  Miss  li.  A.,  statement  of, 19,25 

McGowen  nozzle, 152 

McKee,  George  W.,  bark  shave  invented  by, 190 

McLaughlin,  Wm.,  statement  of,          .......        44 

Medford,  brick  shipments  from, .         .        .         .        i        .        .         .110 

centre  of  infestation,     .........        99 

colonies  of  gypsy  moth  discovered  in  woods  of,  .        .        .        .        85 

description  of  section  8  (Appendix  C). 

distribution  of  caterpillars  from 112 

gypsy  moth  fought  by  municipal  authorities  of 33 

measures  taken  to  destroy  the  pest  in, .        .        .        .        .        .        34 

"Mercury,"  description  by  ^.   0.  Goodwin  of  movements  of 

caterpillars  in,          .  13 

residence  of  Trouvelot  in, 4 

selectmen  of,  petition  for  extermination  of  gypsy  moth  pre- 
sented to  Legislature  by, 36 

statement  of  citizens  as  to  escape  of  gypsy  .moth,       ...          4 

trees  defoliated  by  gypsy  moth  in 57 

woodland  burned  in, 166 

Meeting  of  Board  of  Agriculture,  special, 49 

opponents  to  spraying, 56 

Meigenia  bisignata, 392 

Melrose,  outbreak  of  the  gypsy  moth  in, 58 

Men,  examination  and  training  of C8,  85 

largest  force  of 85 

Menecles  insertus, 393 


INDEX.  Ixxxv 


PAGE 

Mephitis  mephitica, 404 

Method  of  pruning, 177 

of  rearing  predaceous  insects 384,394 

of  testing  insecticides 418 

pursued  in  outside  inspecting, 60 

Methods  for  destroying  the  gypsy  moth 164 

in  Europe, 284 

most  useful  to  the  farmer, 194 

Metropolitan  Park  Commission,  gypsy  moth  committee  hold  meet- 
ing With, 78 

location  of  territory  controlled  by  the, 78 

reservation,  moths  found  in  the, 86 

"  Mercury,"  Medford,  description  of  movements  of  caterpillars  in,  .  13 

Merrill,  Mrs.  E.  E  ,  statement  of, 42 

^ferula  migratoria,         ..........  216 

Mesochorus,  species  parasitic  on  gypsy  moth  in  Europe,     .        .         .  378 

Microgaster  species,  parasitic,  on  gypsy  moth  in  Europe,  .        .        .  377 

value  of  certain  species  in  Europe,        ......  288 

Micropyle,  description  of, 289 

Middlesex  Fells,  colonies  of  gypsy  moth  found  in  the,      ...  86 

condition  of, 87 

Migration  of  the  gypsy  moth  in  search  of  food,          ....  97 

Milk  inspectors,  information  furnished  by, 107 

peddlers,  distribution  of  gypsy  moth  by 109 

Miller,  J.  C.,  statement  of, 13,  42 

Minott,  C.  W.,  experiments  by 418 

observations  on  feeding  habits, 311 

observations  on  vitality  of  larvae, 299 

observations  on  creosote  oil,         .......  416 

Mirror,  use  of, 125 

Mites  attacking  eggs, .        .        .        .404 

Mixter,  C.  S.,  statement  of,         .        .        .                 .        .        .        .  41 

Molting  of  the  gypsy  moth, 308 

Molts  of  gypsy  moth  larvae,          .        .        .        .  •      .        .        .        .  304 

time  between, 305 

Mongoose,  importation  into  Jamaica, 233 

Monteiro,  Dr.  A.  A.  C.,  on  egg-killing 118 

Morton,  Hon.  J.  Sterling,  matter  of  appropriation  presented  to,        .  83 

Moscow,  occurrence  of  gypsy  moth  in,                .  '      .        .        .       268,  283 

Mosher,  F.  H  ,  experiments  by, 418 

observations  on  blue-jay, 214 

observations  on  crow, 217 

observations  on  cuckoo, 212 

observations  on  flight  of  female, 344 

observations  on  hairy  woodpecker, 221 

observations  on  tree  frog 404 

observations  on  vitality  of  larvae, 299 

Moth,  gypsy.     See  Gypsy  moth. 

gypsy,  female.     See  Female  gypsy  moth. 

gypsy,  male.     See  Male  gypsy  moth. 

traps,      358,  360 


Ixxxvi  THE   GYPSY   MOTH. 


PAGE 

Moth,  tussock,  increase  due  to  sparrows, 235 

Moulton,  F.  C.,  analyses  by, 474 

experiments  by, 142,  407 

on  cyanides, .       485 

Myiarchus  crinitus, 207 


jr. 

Names  of  gypsy  moth, 255,  256 

Naphtha  burner  for  destroying  caterpillars,      '  .        .        .        .       122,  126 

Nason,  Prof.  F.  L.,  inventor  of  dendrolene, 135 

Nasonov,  Dr.  N.,  on  egg-killing, 118 

on  methods  of  destroying  the  gypsy  moth, 284 

on  ravages  of  gypsy  moth  in  Poland,    .        .         .         .        .         .283 

Native  birds  driven  away  by  sparrows, 234 

Natural  enemies  of  gypsy  moth, 95,  96 

birds, 203 

Coleoptera, 381 

Diptera 385 

Hemiptera 392 

Hymenoptera 375 

spiders 404 

vertebrates, 404 

selection,  effect  on  gypsy  moth  in  England,          ....       273 
selection,  influence  on  colors  of  gypsy  moth,       ....      272 

selection,  influence  on  flight  of  males, 345 

Neitner,  gypsy  moth  found  in  Ceylon  by, 267 

Nematus  erichsonii,  damage  from, 270 

ribesii,  damage  from, 270 

Nervous  system  of  gypsy  moth, .        .       373 

Neville,  T.  J.,  statement  of,         .        .        .        .  .         .        23 

Nicholson,  C.,  on  extermination  of  the  gypsy  moth  in  England,         .       270 

Nitric  acid  for  destroying  eggs, 123 

Nitrogen  dioxide  for  destroying  eggs, 413 

Noctua-c-nigrum,  . 400-402 

Nolken  on  distribution  of  gypsy  moth,        .        .        ...        .268 

Norcross,  J.  Henry,  efforts  of,  to  secure  an  appropriation,         .        .        36 
Nothrus  sp.  attacking  gypsy  moth,       .        .        .     "  .        .        .        .      404 

Nozzle,  cyclone,  for  burning, .       120 

gem,  used  for  contact  insecticides, 163 

Nozzles  for  spraying 147,  149,  150,  154 

Number  of  caterpillars  from  single  egg-clusters,         ....       297 

Nun  moth,  aerostatic  hairs  of, 301 

damage  by  {see  Lymantria  (Liparis)  monacha),    ....       130 

Nursery  stock,  where  shipped, 108 

Nuthatch  attracted  by  meat, 229 

feeding  habits  of 23  L 

white-breasted,  attacking  the  gypsy  moth, 208 

Nymphcea  odorata, 317 


INDEX.  .      ixxxvii 

O. 

PAGE 

Oak  attacked  by  gypsy  moth  in  Europe,      .        .         .         274-277,  281-283 

leaf,  area  of, _ 495 

Obstacles  to  extermination,          .        .        .        .        .        .        .        .       245 

Ochsenheimer,  "  Schmett.  v.  Europa,"  •  .        .        .        .        .       255 

Ocneria  dispar,      .  .        .  .        .        .        .        .      255 

act  to  provide  against  depredations  by,         .        .        .        .        .        47 

See  Gypsy  moth. 
Ocneria  rnbea,  peculiar  structure  on  fore  wings  of,    .        .        .        .      342 

studies  on, 256 

Odoriferous  glands  of  bugs,          .        .        ..-.-.        .        .      394 

Oil,  creosote,  for  destroying  eggs, 63,  123,  410 

hose, .  .        .        .120 

parafflne  gas,  used  for  burning, 120 

paraffine  gas,  used  on  eggs, .        .      417 

rape,  with  tar  for  banding  trees, 285 

spray,  burning  with, 59 

Old  World,  injuries  of  gypsy  moth  in, 273 

Orchards  attacked  by  gypsy  moth, 274 

extermination  of  moth  in, 248 

Orenboorg,  ravages  of  gypsy  moth  at, 280 

Organization  of  committee, 38,  49 

of  field  force, 50 

of  second  commission, 45 

Orgyia  definita,  influence  of  environment  on, 273 

leucostigma,       .  402 

compared  with  gypsy  moth 272 

destroyed  by  spraying,  .        .        .        .        .  .        .        .140 

increase  due  to  English  sparrows,         .        .      • ,        .        .        .      235 
Oriole,  Baltimore,  attacking  the  gypsy  moth,     .        .    6,  213,  225,  227,  237 

Osborn,  Prof.  Herbert,  identification  of  mites, 404 

Outbreaks  of  the  gypsy  moth  checked  by  birds,          ....      205 

of  the  gypsy  moth  in  1889,     ....'...»        10 

Oven  bird  attacking  the  gypsy  moth,  .        .        .        .        .        .       208,  219 

Oviposition  of  gypsy  moth,          .        .        .        ...        .        .        .      363 

Ovipositor  of  gypsy  moth,  .        .         .  .        .        .        .        .342 


P. 

Packard,  Dr.  A.  S. ,  infested  region  visited  by, 69 

report  of  (Appendix  D). 

Paint  and  creosote  tube, 124 

for  use  in  marking  trees, 51,  124 

for  use  on  wounds  on  trees, 178 

town  section  bounds  marked  with, 50 

Palsacrita  vernata, 402 

food  plants  of  the, 97 

Palpi,  labial,  used  in  spinning, 332 

of  imago, 339 


Ixxxviii  THE   GYPSY  MOTH. 


PAGE 

Panzer  on  ravages  of  gypsy  moth, 275 

Parafflne  gas  oil  for  burning, 120 

gas  oil  on  eggs, 417 

Parasitized  pupae,  per  cent,  of, 336 

Parasites  of  gypsy  moth,      . 375 

aid  given  by,  in  Europe,         .        .     - -..;'• 284 

breeding,  on  many  hosts, 377 

destroyed  by  birds, 220,241,376 

dipterous 385 

hymenopterous, 375 

importation  of, 406 

on  eggs, 63 

vegetable, 405 

Parexorista  sussurans, 392 

Paris  green, 39,  56,  58,  59,  80,  137,  138,  417,  419,  473 

analyses  of, 492 

Paris  green  and  lime,  analyses  of, 492 

comparative  effects  of 473 

experiments  with, 436 

on  foliage, 491 

Parasitigena  segregata, 392 

Park,  Franklin,  Boston,  colony  of  gypsy  moths  found  in,        •  .         .  70 

reservation,  Metropolitan,  moths  found  in,          ....  86 

Parks,  possible  danger  to 87 

Parthenogenesis, 365 

Parus  atricapillus.     See  Chickadee. 

major, 233 

Passerina  cyanea, 207 

Pearce,  W.  J.,  on  parthenogenesis, 367 

Peddlers,  routes  of, 108 

Pedestrians,  distribution  of  the  gypsy  moth  by,          ....  103 

Pekin,  gypsy  moth  occurring  at, 268 

Penza,  ravages  of  the  gypsy  moth  in, 281 

Pergande,  Theo.,  identification  of  ants  by, 381 

Perillus  circumcinctus, 393 

Perkins,  Dr.  G.  H.,  infested  region  visited  by, 79 

report  of  (Appendix  E), 

Perry,  A.  P.,  statement  of, 21 

Pesomachus  hortensis, 378 

Petition  by  city  officials  of  Maiden 36 

by  city  officials  of  Somerville,       .        .        .        .....  36 

by  Essex  County  Agricultural  Society,                  ,        .        .        .  36 
by  executive  committee  of  the  State  Board  of  Agriculture,         .  36,  78 

by  Massachusetts  Horticultural  Society,      .     . •  .,       .        .        .  35 

by  selectmen  of  Arlington,    .        .....        .        .  36 

by  selectmen  of  Everett 36 

by  selectmen  of  Stoneham, 36 

by  selectmen  of  Wakefleld, 36 

by  selectmen  of  Winchester, 36 

by  State  Board  of  Agriculture 36 

Petroleum,  use  of,  on  eggs, 119,288 


INDEX.  Ixxxix 


PAGE 

Pewee,  wood,  attacking  the  gypsy  moth, 207,227 

destroying  parasites, 220,  376 

Phalcena  (Bombyx)  dispar, 255 

Phalangium  dorsatum, 404 

Phenol  on  eggs,    .        .        .        .        .        .        .        .        .        .       123,  414 

Phidippus  galathea,       .        .        .        .  .        .        .        .        .      405 

Phidippus  tripunctatus,  .        .     »  . .       404 

Phloeothrips,  .....     •--.        .      •  .  .         .         .404 

Phoebe  attacking  the  gypsy  moth, .       207,  227 

Phora  incisiiralis, .         .        . 387 

scalaris, 387 

setacea, •        .  391 

Phorocera,     .         .        .        .        .        .        ....        .        .      387 

Phorocera  concinnata, 392 

Phosphoric  acid  deposits  in  caterpillar, 370 

Pierce,  G.  T.,  statement  of, 41 

Pierce,  Richard,  statement  of, 21,  29,  43 

Pierce,  W.  A.,  at  conference  on  gypsy  moth  (Appendix  A),  .        45 

Pieris  rapce,  damage  from •    .         .       270 

Pimpla  flavicans .        .        .      378 

instigator, .         .      378 

pedalis, 375,  377 

tenuicornis, .        .      375 

Pines  attacked  by  the  gypsy  moth,       .        .        .        .      .  .        .         86,  277 

attacked  by  the  gypsy  moth  in  Europe, 282 

Pipilo  erythrophthalmus .        .207 

Piranga  erythromelas, 207 

Pitch,  trees  banded  with .        .        .      285 

Plants  attacked  by  the  gypsy  moth,     .        .        .        .58,  70,  316,  318,  323 

in  Europe, .      325 

not  attacked  by  the  gypsy  moth, 323 

Plaster  of  Paris,  use  of,  on  trees, 188 

Platynus  limbatus, 384 

Plummer,  Mrs.  A.  H.,  statement  of,    .        .  .        .        .     29,31,42 

Podisus  cynicus,    .        .  •  .         .        .        .         .  .         .       392 

serierentris,       .        : 393 

early  stages  of ,  ...        .        .        .        .        .        .396 

Poisoned  larvae,  analyses  of, 474 

Poland,  ravages  of  the  gypsy  moth  in  forests  of,       ....       283 
Police  regulations,  enforcement  of ,     .       -..     '.        .        .        .        .54,55 

Polistes  pallipes, ; 378 

Poltava,  ravages  of  the  gypsy  moth  in,  .        .        .        .        .       281 

Polygamy  of  the  gypsy  moth, 343 

Pomerania,  insect  outbreak  in, 205 

Pontederia  cordata, 317 

Population  of  Massachusetts,  proportion  of,  in  infested  region,       .       101 

relation  of,  to  distribution, 99 

Porchinsky,  Dr.  J.,  on  means  of  distributing  the  gypsy  moth,  .        .      286 
on  ravages  of  the  gypsy  moth  in  the  Crimea,       .        .        .        .279 

Porthetrta  dispar, 255 

systematic  position  of  (see  Gypsy  moth) , 256 


xc  THE   GYPSY  MOTH. 

PAGE 

Post  offices,  frames  placed  in, 199 

Potassic  cyanide  on  eggs, 413 

Potato  beetle  killed  by  arsenate  of  lead,      .         .         .         .  .144 

Pratt,  Augustus,  elected  a  member  of  the  committee,         ...  76 

Predaceous  Coleoptera, 381 

Diptera, 392 

Hemiptera 392 

Hemiptera  attacked  by  crows,       ....                 .        .        .  394 

Hemiptera,  how  reared, 394 

Hymenoptera, 378 

insects,  aid  given  by, 284 

insects  destroyed  by  birds, 241 

insects,  Dr.  Altum  on  importation  of, 288 

Press,  State,  assistance  given  by, 199 

Primary  distribution  of  the  gypsy  moth 104 

Printers'  ink  used  in  protecting  trees  from  gypsy  moth,     ...  34 

Process  of  emerging, 336 

of  molting, 308 

of  pupation, 332 

Progress  of  extermination 244 

Protection  of  birds,  law  for, 206,  242 

Protoparce  celeus,  granules  in, 370 

Pruning,  effects  of  improper 175 

infested  trees, 172 

season  for, 179 

Preyssler,  on  ravages  of  the  gypsy  moth, 275 

Pteromalus  boucheanus,        .                  377 

holiday  anus,        .........  377 

pini, 377 

Ptinus  brunneus, 385 

Pumps,  Gould, •     .    •     .        .        .150 

how  repaired, *        ....  156 

knapsack 149 

Pupae  of  the  gypsy  moth,  arsenic  found  in, 476 

assembling  by, 363 

attacked  by  parasites 376 

birds  feeding  on, 7,  208,  228 

comparison  of  number  of,  destroyed  annually,     ....  93 

description  of,        .        .        .        .        .        .        .        .        ;        .  333 

destruction  of,        .         .        .        .1.        ;        .-       .        .58,59,194 

emerging  of  imago  from,      .        .        ....        .         .  336 

parasites  rearc-d  on .*.••.        .        .  386 

per  cent,  parasitized, 336 

size  of,                     * 333 

time  spent  in, 333 

Pupation  in  the  field 335 

process  of, 332 

Purple  grackle  attacking  the  gypsy  moth, 207 

Pyroligneous  acid  on  eggs, 416 

Pyrophila  pyramidoides, 402 

Pyrrharctia  Isabella, 377 


INDEX.  xci 


Q. 

PAGE 

Quercus  pedunculata  attacked  by  gypsy  moth 282 

rubra,  leaf  area  of, 495 

Quiscalus  quiscula, 207 

R. 

Kailroad  sidings,  inspection  of, Ill 

trains  obstructed  by  gypsy  moth, 280 

Railroads  running  through  the  infested  district,          .        .        .       101,  102 
Bana  silvatica,       .         .  .         .        .        .         f        .         .         .404 

Ransom,  Miss  M.  M.,  statement  of,    .        .  .        ,        .20,27,29 

Ratzeburg  on  ravages  of  the  gypsy  moth,  ......       277 

Raupenleim  bands,        .        .        .        .        ...        .        .        129-135 

composition  of,      .         .        .         ...        .        .        .         .       135 

on  eggs, 125,  284,  285,  417 

trees  banded  with,          .        .        .        .        .        ...        .  64,  69,  136 

Ravages  of  the  gypsy  moth  in  Massachusetts,    .        ...        .        .     7-44 

of  the  gypsy  moth  in  Old  World 273 

Rawson,  W.  W.,  appointed  commissioner, .        .        .        .        .        .        38 

Reaumer  on  birds  destroying  the  gypsy  moth, 232 

Red-eyed  vireo  attacking  gypsy  moth,         ......       207,216 

Redstart,  American,  attacking  the  gypsy  moth,.        .        .        208,  219,  227 
Reduction  of  infested  area, .        .        .        .        .        .        .        .        .      245 

Region,  infested.     See  Infested  region. 

Regulations  concerning  the  gypsy  moth  (Appendix  B). 

Reid,  H.  N.,  experiments  by, 418 

on  trapping  males,         .        .        •  .        .        .        .        .      357 

Reply  of  State  Board  to  order  of  Representative  W.  J.  D.  Bullock,        73 

Reports  of  inspectors, .        .  51,  52 

of  State  Board  of  Agriculture,  extracts  from,      .          65-67,78,81,82 
of  visiting  entomologists  (Appendix  E),      .        .•       . 

Reproductive  powers  of  gypsy  moth,  .  245 

system  of  gypsy  moth, 373 

Respiratory  system  of  gypsy  moth, '.      372 

Restriction  of  distribution  of  gypsy  moth, 114 

Retractile  tubercles  of  gypsy  moth  larva 302 

secretion  from, 304 

Ehynchagrotis  alternata, 400,  402 

Riazan,  ravages  of  gypsy  moth  in, 281 

Richardson,  D.  M.,  statement  of, 12,  27 

Riegel,  on  ravages  of  gypsy  moth,       .......      277 

Riley,  Prof.  C.  V.,  at  conference  on  gypsy  moth  (Appendix  A),        .        45 

infested  district  visited  by, 56 

on  assembling  in  the  bombycidae, 357 

on  insectivorous  birds, 207 

on  occurrence  of  gypsy  moth  in  America, 3 

Rimrod,  C.  J.,  on  ravages  of  gypsy  moth, 275 

Ritzema-Boz,  Dr.  J.,  on  gypsy  moth  in  Holland,        .        .        .       268,  283 
Road  commissioners  of  Medford,  meeting  of 33 


THE   GYPSY  MOTH. 


Roads,  destruction  of  eggs  along, 63 

isolated  colonies  found  along  the, 54 

Robert,  M.,  on  tree  scraping 191 

Robin,  American,  attacking  the  gypsy  moth,       .        .         .        208,216,227 

destroying  predaceous  insects, 241 

destruction  of  silk  worms  by, 6 

experiments  on, .        .        .         .      204 

Rogers,  J.  H.,  statement  of ,         ........         17 

Romanoff  on  distribution  of  gypsy  moth,    ......      268 

Rose-breasted  grosbeak  attacking  the  gypsy  moth,     .         .         .       207,  219 

Routes  of  transportation,  study  of  the 106 

Rowe,  C.  H.,  on  predaceous  beetles, 381,382,385 

Rubbish,  destruction  of, 193 

Rudzky,  on  egg  destruction, 285 

Rules  and  regulations  concerning  the  gypsy  moth  (Appendix  B), 

Russell,  G.  C.,  statement  of,         . 21 

Russell,  Gov.  Wm.  E.,  removal  of  salaried  commission  by,       .         .        45 

Russell,  Mrs.  E.  M.,  statement  of 21 

Russia,  occurrence  of  gypsy  moth  in, 268 

ravages  of  gypsy  moth  in, 279,  280 

Ryder,  Mrs.  P.  N.,  statement  of, 43 

s. 

Salisbury  on  occurrence  of  gypsy  moth  in  England,  ....       268 

Samara,  ravages  of  gypsy  moth  in, 281 

Samuels,  E.  A.,  record  of  destruction  of  silkworms  by  birds,   .        .          6 

on  value  of  birds, 205 

Sanderson,  L.  B.,  notes  on  wood  thrush 236 

statement  of , .        59 

Sap,  circulation  of ,  in  trees, .175 

Saratov,  ravages  of  gypsy  moth  in,      .         .        ....        .       281,282 

Sarcophaga,  parasitic 387,  389 

Sarcophaga  affinis, 392 

Sargent,  Dr.  C.  S.,  translation  of  Des  Cars'  "  Tree  Pruning"  by,  .  179 
Sargent,  F.  W.,  elected  member  of  the  committee,  ....  76 

Saugus,  gypsy  moth  found  in, 53,  86,  87 

Saxony,  ravages  of  gypsy  moth  in,  .        .        .'        .        .        .      274 

Sayornis  phcebe.     See  Phoebe. 

Scales  of  gypsy  moth  wings,  form  of ,  .....  341,342 
Scarlet  tanager  attacking  the  gypsy  moth, .  .  -^  .  .  .  207,  227 
Scattered  eggs, *.  .  .  63,117,363 

eggs,  fertility  of 239 

Scattering  of  caterpillars, 114 

Schaeffer,  J.  C.,  on  ravages  of  gypsy  moth  in  Saxony,        .        .        .      274 

Scheffer,  M.,  on  use  of  burlap, 171 

Scheuerlen,  Dr.,  on  disease  of  nun  moth 405 

Schmidberger  on  egg-killing, 117 

Schrader,  F.  C.,  experiments  by, 360,  418 

Schrank  "Fauna  Boica," 255 

Scolytidse,  attacking  trees, 190 


ESDEX.  xciii 

PAGE 

Scolytus  destructor  attacking  trees  in  England, 192 

Scraping  of  eggs  from  trees,  method  of,  discarded,  ....  63 
of  eggs  from  trees,  recommended  by  Europeans,          .        .        .292 

of  trees 189 

of  trees,  value  of , 172 

Scudcler,  Samuel,  at  conference  on  gypsy  moth  (Appendix  A),          .  45 

Season  for  pruning, 179 

larval,  distribution  in,    .        .       v- -••-., 110 

Second  brood  of  the  gypsy  moth,        .        .  .        .        .         86,295 

"  Section"  books,  record  of  infested  estates  kept  in,         ...  52 

Section  8,  Medford,  description  of  (Appendix  C). 

Sections,  towns  divided  into,       .        .        .        .        .        .        .        .  49 

Seitz,  raupenleim  machine,  .........  133 

Seopru,  Georg,  on  ravages  of  gypsy  moth  in  the  Crimea,  .        .        .  280 
Sessions,  Hon.  Wm.  R.,  appointed  member  of  committee,         .        .49,76 
at  conference  on  gypsy  moth  (Appendix  A). 

chosen  chairman  of  committee, 49 

Medford  visited  by,        .        .        *        .        .        .        f        .        .  34 

member  of  committee  sent  to  Washington, 83 

Sex  differentiation  in  larvae, .        .  374 

Sexual  dimorphism  of  gypsy  moth, 272 

Shade  trees,  how  sprayed, 158 

Shaler,  Prof.  N.  S.,  appointed  member  of  committee,         ...  49 

assistance  given  by, .        .  72 

at  conference  on  gypsy  moth  (Appendix  A),        .        ...  45 

interview  with  Mr.  Trouvelot, 4 

resignation  of, 72 

Shaw,  H.  J.,  moth  trap  invented  by, 360 

observations  on  red-eyed  vireo 221 

Shellac,  use  of,  in  pruning, 177 

Sherman,  J.,  statement  of, 20 

Sherman,  Walter,  statement  of, 20,  26 

Shipov,  ravages  of  gypsy  moth  in,       .......  282 

Sialia  sialis.     See  Blue  bird. 

Siberia,  occurrence  of  the  gypsy  moth  in,  .        .        .        .        267,  268,  280 

Sidings,  railroad,  inspection  of, Ill 

Siebold  on  parthenogenesis .366 

Silk,  amount  spun  by  gypsy  moth  caterpillars 331 

glands  of  caterpillars, 370 

Silkworms  destroyed  by  birds, 6 

Silpha  quadripunctata, 287 

Simbeersk,  ravages  of  gypsy  moth  in, 281,283 

Sinea  diadema 405 

Size  of  imago,  variation  in, 338 

Skunk  attacking  the  gypsy  moth, 404 

Smith,  Prof.  J.  B.,  infested  region  visited  by, 69 

on  insectivorous  birds, 207 

on  raupenlein, 135 

on  systematic  position  of  dispar, 256 

report  of  (Appendix  D). 

Smith,  J.  W.,  data  furnished  by,  concerning  wind,     ....  350 


xciv  THE   GYPSY  MOTH. 

PAGE 

Snowdon,  W.  H.,  statement  of, 13,18,25,30 

Soap  powders,  use  of,  as  contact  insecticide,      ....       163,  485 

Soda,  arsenate  of,  experiments  with, 143 

Somerville,  petition  presented  by  city  officials  of,       ....        36 

Sorauer,  Dr.  Paul,  on  tree  pruning, 181 

South,  Eichard,  on  extermination  of  gypsy  moth  in  England,  .        .       269 

Spain,  occurrence  of  gypsy  moth  in, 268 

Sparrow,  chipping,  feeding  on  gypsy  moth  caterpillars,     207,  215,  226,  227 

English,  attacking  the  gypsy  moth, 208 

English,  feeding  on  gypsy  moth  eggs, 231,239 

English,  introduction  of, 233,  234 

Sparrows  feeding  on  gypsy  moth,        .  ....       219,228 

Speyer  on  distribution  of  gypsy  moth, 267 

Sphinx  drupiferarum, 383 

Spiders  attacking  gypsy  moth, 404,  405 

"  Spiegel,"  destruction  of, 284 

Spines  on  wings  of  gypsy  moth, 341 

Spinney,  Mrs.  F.  T.,  statement  of, 12,  18,  29,  32 

Spinning  habits  of  caterpillars, 102,  278,  330,  332 

Spiny  area  on  wings, 341 

Spizella  socialis 207,  215 

Spray,  burning  with  oil, 59 

Spraying  against  gypsy  moth, 157 

apparatus, 145-156 

benefit  to  fruit  crops  from, 60 

burlapping  substituted  for 64 

caterpillars  distributed  by, 113 

caterpillars  killed  by 57,  58,  64 

danger  from  (Appendix  F) , .        . 

distribution  lessened  by, 64 

poisons  for  use  in,          .         .        .      •  .        ...         55,417,477 

not  effectual  as  an  exterminative  method, 56 

number  of  moths  destroyed  by,     .        .        .        .        .        .        .        92 

prejudices  against,         .         .        .         .         .        .        .         .       118,  199 

recommended  by  entomologists  (Appendix  A),    .         .         .        .45,55 

rules  concerning  (Appendix  B). 

system  of, 56 

time  of, .        .       156,  157 

with  arsenate  of  lead,     .        .        .       . .        .     •  -.        .         .        .        87 

with  arsenate  of  lead,  effectiveness  of, 80 

with  arsenical  insecticides,  failure  of,  as  a  means  of  extermina- 
tion,         .  62 

with  contact  insecticides, 67 

with  Paris  green.     See  Paris  green. 

with  Paris  green,  opposition  to, 56 

outfits, 55,  140 

Spread  of  gypsy  moth,  comparison  with  that  of  canker  worm,         .        97 

efforts  to  prevent  the, 79 

in  twenty  years, 5 

in  woods, 115 

slow, 245 


INDEX. 


Squirrels,  eggs  scattered  by, 231 

Starling  attacking  nun  moth  in  Europe, 208,  209 

State  Board  of  Agriculture.     See  Board  of  Agriculture. 
Statements  of  citizens  concerning  the  gypsy  moth  (Appendix  G),     7,  8-10, 

11-13,  14-32,  33,  40-44,  59 

Station,  experiment,  erection  of, 87,  406 

Staudinger  on  distribution  of  gypsy  moth, 267 

Steatoda  borealis, 405 

Stephens,  "  Illustrations  of  British  Entomology,"      ....  255 

on  occurrence  of  gypsy  moth  in  England, 269 

Stephenson,  Dr.  F.  B.,  translation  of  Kussian  works  on  gypsy  moth 

by,   .        .        . 268 

Stetson,  John,  statement  of, 10 

Stetson,  S.  S.,  elected  a  member  of  the  gypsy  moth  committee,        .  84 

Stockholm,  occurrence  of  gypsy  moth  at,  .        .        .        .        .        .  267 

Stomach  examination  of  cuckoo, 212 

examination  of  toad,    '.'•-.        .        .        .        .  .        .405 

of  gypsy  moth  larva, .  369 

Stoneham,  petition  presented  by  selectmen  of, 36 

Stone  walls,  comparison  of  yearly  work  on, 93 

St.  Petersburg,  non-occurrence  of  gypsy  moth  at,              .        .        .  268 

Streams,  caterpillars  distributed  by, 98 

Studies  on  systematic  position  of  dispar, 266 

Study  of  the  methods  and  routes  of  transportation,  ....  106 

Sulpho-naphthol, 484 

Sulphur  dioxide  on  eggs, 416 

Summer  pruning, 184 

Swallows,  house,  driven  away  by  sparrows, 234 

Swampscott,  outbreak  of  the  gypsy  moth  in, 58 

Sweden,  occurrence  of  gypsy  moth  in, 267 

Swill-takers,  distribution  of  the  moth  by, 109 

Swinton  on  sound  producing  insects 341 

Syrphus  sp.  attacking  the  gypsy  moth, 405 

Systematic  position  of  dispar 256 


T. 

Tachina,  European  parasites  of  gypsy  moth 392 

Tachinids  captured  by  birds, .241 

parasitic,         ..         .........      387 

Tambov,  ravages  of  the  gypsy  moth  in, 281 

Tanager,  scarlet,  attacking  the  gypsy  moth,       ....       207,  227 
Tangl,  Dr.,  on  disease  of  nun  moth,   .        .        .        .        .        .        .      405 

Tar  and  rape  oil  bands, ...      285 

bands, 127,  285,  286 

coal,  use  of,  in  tree  pruning, 177,  182,  186 

used  on  eggs, 125,  414 

Tarred  burlap,  use  of,  on  trees 188 

paper,  trees  banded  with, 28 

Taylor,  Wm. ,  statement  of, 8,19,25,28,31 


xcvi  THE   GYPSY   MOTH. 


PAGE 

Teaming  from  infested  region, 108 

Telea  polyphemus, 401,402 

Tent  caterpillars  attacked  "by  warblers, 219 

caterpillars  destroyed  by  Baltimore  oriole, 213 

caterpillars  destroyed  by  spraying 140 

caterpillars  killed  by  arsenate  of  lead, 144 

Terns  as  insect  destroyers, 206 

Territory  infested.     See  Infested  region. 

Thaxter,  Dr.,  on  vegetable  parasites, 405 

Thelymorpha  vertiginosa,       .        .        . 392 

Theronia  melanocephala, 375 

destroyed  by  wood  pewee 220,  376 

habits  of, 376 

Thomixus  sp.  attacking  the  gypsy  moth, 405 

Thrush,  brown,  feeding  on  the  gypsy  moth,       ....       208,  225 

wood,  feeding  on  the  gypsy  moth, 208,  236 

Tideman  on  ravages  of  the  gypsy  moth  in  Kazan,      .        .        .        .281 

Time  between  molts, .  v    305 

in  pupa  stage, 333 

of  feeding 311 

of  hatching, 294 

record  of  men's, 52 

required  for  emerging, 336 

spent  in  laying 364 

spent  in  mating, 342 

spent  in  spinning, 332 

Tin,  use  of,  on  trees, .       189 

Tirestas  serra, .        .       385 

Titmouse  attacking  the  gypsy  moth  in  Europe,  .        .        .        209,  232,  233 

attracted  by  meat, 229 

great,  attacking  other  birds  (see  chickadee) .....      233 

Toad  attacking  the  gypsy  moth, .       222,  404 

Tobacco  mixture  as  an  insecticide,      .        .        .        .        .        .        .483 

Tolype  velleda, .        .        .        .        .      402 

Torches,  kerosene,  for  burning  caterpillars, 39 

Tortricids,  British,  dark  color  of, 271 

Tortrix  fumiferana  attacked  by  Pimpla  pedalis,          ....      377 
Tower,  W.  L.,  notes  on  caterpillars,   .        .        .'      .        .        .       169,329 

on  predaceous  Hymenoptera, 379 

Towhee  bunting,  feeding  on  gypsy  moth  imagoes,      .        .        .       225,  227 
Towns  and  cities  from  which  false  alarms  have  been  received,         .      201 

divided  into  sections, 50 

efforts  concentrated  in  outlying, 53 

infested,  citizens  from,  present  at  hearings,         ....        84 
infested,  proportionate  numbers  of  gypsy  moths  in,    .        .        .        99 

inner,  increase  of  the  moths  in, 92 

inspected  beyond  infested  area, 198 

necessity  of  inspecting  apparently  cleared, 80 

worst  infested,  destruction  of  eggs  in, 69 

Traffic,  danger  from, 109 

distribution  of  the  gypsy  moth  by, 102 


IXDEX.  xcvii 


PAGE 

Traffic,  ratio  of  distribution  by, 109 

study  of, 109 

Transportation,  a  study  of  the  methods  and  routes  of,       .        .        .       106 

by  freight, 110 

Trapping  of  male  moths,  results  of, 80,  357 

Traps,  caterpillar, -.        .         .311 

moth, 358,  360 

Travel,  danger  from,  to  Boston, 107 

direction  of,  from  infested  centre, 107 

lines  of, 108 

Travelling  of  young  larvae .        .        .        .310 

Treadwell,  Professor,  experiments  on  robins, 204 

Tree  creepers  attracted  to  meat, 229 

Tree  ink,  trees  banded  with,         .        .        ...        .        .        .         64,128 

pruning, 172 

Trees,  alarming  condition  of,  In  1889, 33 

banded,  .  126, 195 

banded  with  burlap, 69,  85,  167 

banded  with  raupenleim,        .  64 

banded  with  tarred  paper, .        .        28 

banded  with  tree  ink .        .        64 

comparison  of  yearly  work  on, .92,93 

defoliated  by  the  gypsy  moth,       .        .        .        .        .        .        .  57,  85 

destroyed  by  the  gypsy  moth,        .        .        .        .        .        .  23,  70,  274 

hollow,  treatment  of, 63,  187 

infested,  location  of, .        .        99 

infested,  marked  with  white  paint 51 

leaf  area  of, 494 

per  cent,  of  pupae  in,      .........      335 

saved  by  contact  insecticides,        .......        58 

scraping  of, 189 

Trogus  flavatorius, 878 

Trombidium  bulbipes,    .         .        .,...,.        .         .         .404 

Trouvelot,  Leopold,  interview  with  Prof.  N.  S.  Shaler,      ...          4 

introduction  of  the  gypsy  moth  into  America  by,         ...          3 

residence  in  Medford, 4 

Tube,  paint  and  creosote, 124 

Tubercles,  larval, 300 

retractile, 303,  304 

Tubeuf,  Dr.,  on  disease  of  nun  moth, 405 

Turpentine  for  destroying  eggs, 123,  416 

Tussock  moth  destroyed  by  spraying, 140 

increase  of,  due  to  sparrows, 235 

Tutt,  J.  W.,  on  the  extermination  of  the  gypsy  moth  in  England,     .       270 

Tuttle,  Mrs.  R.,  statement  of, 11,16,25 

Tyrannus  tyrannus, 207 


xcviii  THE   GYPSY  MOTH. 


U. 

Uhler,  Prof.  P.  R.,  description  of  Podisus  serieventris,        .        .        .399 

determination  of  Hemiptera  by 400 

Unfertilized  females,  eggs  laid  by, 290,  365,  367 

United  States  Senate,  resolve  passed  by  the, 83 

Urates,  presence  of,  in  malpighian  vessels  of  larvse,  ....      370 

Useful  birds 210 

insects  v.  birds, 240 

Utah,  cricket  ravages  in, 206 

Y. 

Value  of  egg-eating  birds,    . 229 

Vanessa  antiopa, 400,  402 

Variation  in  size  of  imago, 338 

Vegetable  parasites, 288,  405 

Vehicles  inspected  by  police, 54 

transportation  of  the  gypsy  moth  by,   .         .        .          39,  102,  103,  107 

Vertebrates,  insectivorous, 404 

Vespa  consobrina 378 

germanica, 378 

maculata, 378 

Villages,  inspection  of, 197 

Vireo,  red-eyed,  attacking  gypsy  moth  caterpillars,    .         .        207,  21G,  225 

white-eyed,  attacking  the  gypsy  moth, 208 

yellow-throated,  attacking  the  gypsy  moth,          .         .        208,  217,  227 

Vitality  of  dipterous  larvae 386 

of  gypsy  moth  eggs, 279,  291 

of  caterpillars, 299,  325 

of  predaceous  bugs, 393 

Volsk,  ravages  of  the  gypsy  moth  in, 282 

Voronezh,  ravages  of  the  gypsy  moth  in, 281 

w. 

Wachtl  and  Kornauth  on  disease  of  nun  moth,    .  ...       405 

"Wadding  bands,  Klausen's  experiments  with, 286 

Wakefleld,  petition  presented  by  selectmen  of, 36 

Walker,  J.  J.,  on  the  distribution  of  the  gypsy  moth,         .        .        .       268 
Wallace,  Mrs.  B.,  statement  of,  .        .        .....        .        .        44 

Walls,  stone,  comparison  of  yearly  work  on,      .        .        .        .        .        93 

Warbler,  black  and  white,  attacking  the  gypsy  moth,         .         .       208,  225 
black-throated  green,  attacking  the  gypsy  moth,          .        .        .       208 

chestnut-sided,  attacking  the  gypsy  moth, 208 

creeping,  feeding  on  the  gypsy  moth,   .  .        .        .        .227 

Maryland  yellow- throated,  attacking  the  gypsy  moth,          .         .      208 

yellow,  attacking  the  gypsy  moth, 208,  227 

Ward,  A.  H.,  suggestions  on  insecticides  by 142 

Ware,  E.  C.,  directions  concerning  care  of  spraying  machines,          .       155 


INDEX.  xcix 

PAGE 

Warsaw,  occurrence  of  the  gypsy  moth  in, 283 

Wasps,  predaceous, 378 

Water  birds  as  insect  destroyers, 206 

distribution  of  the  gypsy  moth  by, 98,  105 

Wax,  grafting,  use  in  pruning  trees, 177 

Weather,  effect  of,  on  the  moth, 84,  96 

egg  destruction  hindered  by  the, 78 

influence  on  assembling 346 

Webster,  Prof.  F.  M.,  sprayings,  bees 157 

Weed,  Prof.  Clarence  M.,  infested  region  visited  by,  ...  69 
on  feeding  habits  of  the  gypsy  moth,  ....'.  215 
report  of  (Appendix  D). 

Weijnbergh  on  parthenogenesis,          .        .  .        .  ;     .        .366 

Weir,  J.  Jenner,  on  the  extermination  of  the  gypsy  moth  in  England,  270 
Wellington,  Dr.  Chas.,  on  Paris  green  and  lime,  ....  491 
Wellington,  J.  E.,  statement  of .........  30 

Weston,  S.  F.,  statement  of, .        .30,43 

Whale-oil  soap,  use  of, 163,  485 

Wheeler,  J.  G.,  statement  of, .".        .        .  20,  28 

White-breasted  nuthatch  attacking  the  gypsy  moth,  ....      208 

White-eyed  vireo  attacking  the  gypsy  moth, 208 

Wiggin,  Mayor,  at  conference  on  gypsy  moth  (Appendix  A),    .        .        45 

Wild,  Miss  Helen  T.,  statement  of,  13,  21 

Wilkes  on  occurrence  of  the  gypsy  moth  in  England,         .         .        .      268 

Williston,  Dr.  S.  W.,  determination  of  dipterous  parasites  by,  .        .      387 

Winchester,  outbreaks  of  the  gypsy  moth  in,  ...        .        58 

petition  of  selectmen,     .......  36 

Wind,  distribution  of  caterpillars  by, 98,301 

influence  of,  on  assembling 346 

Wingelmuller,  C.,  on  flying  of  female, 344 

Wings,  atrophy  of  female  Orgyia,        .......      273 

effects  of  shellac  on, 351 

form  of  scales  of, 342 

markings  of,  .        .        .  .        .       *        .        .        .        .337 

not  necessary  to  mating, 356 

sound  producing  apparatus  on, 341 

spiny  area  of, 341 

"Winning"  colony,  pupation  in, 335 

second  brood  at, 295 

Winter  oaks  attacked  by  the  gypsy  moth, 282 

pruning, 181 

Woburn,  area  of  infested  woodland  in, 87 

woodland  burned  at, 165 

Wodzicki,  Count,  gypsy  moth  ravages  on  estate  of,  .  .  .  .  232 
Wood,  C.  E.,  observations  by,  on  the  yellow-throated  vireo,  .  217,  222 

Wood,  E.  W.,  elected  chairman  of  committee, 76 

Wooded  region,  inspection  of, 66 

Woodland,  area  of,  infested, 87 

birds  in  infested, 223 

burning  of,     .  165 

colonies  found  in, 70 


c  THE   GYPSY  MOTH. 

PAGE 

Woodland,  area  of,  defoliated  by  the  gypsy  moth,  ....  85 

extermination  of  the  gypsy  moth  in 248 

injury  done  to,  by  the  gypsy  moth 88 

Woodpeckers  attacking  the  gypsy  moth, 207 

attracted  by  meat, 229 

eggs  scattered  by, 230,  231 

feeding  habits  of , 210 

Wood  pewee  attacking  parasites,         .        .        .        .        .        .       220, 376 

attacking  the  gypsy  moth,  .  ...  .  .  .  .207 

Woods,  explanation  of  colonies  in,  .  .  -  *  .  .  .  107 

inspection  of, 87 

moth  checked  in, 88 

result  of  search  of, 80 

Wood  thrush  attacking  the  gypsy  moth, 208 

distributing  gypsy  moth  caterpillars 236 

Work,  cost  of,  increased  by  delayed  appropriations,  ....  78 

delayed  by  snow  storms, 63,  85 

done  annually,  comparison  of 92,  93 

field,  advice  of  Professor  Fernald  concerning,  ....  57 

of  1891, 45 

of  1892 62 

of  1893, 68 

of  1894, 72 

of  1895, 83 

of  four  years,  summary  of, 91 

World's  Columbian  exposition,  exhibit  at, 200 

Wounds  from  pruning,  how  healed, 177 

Wren,  house,  attacking  the  gypsy  moth,  .....  208,  227 

driven  away  by  sparrows, 234 

European,  destroying  eggs  of  the  gypsy  moth 232 

Wright,  Walter,  note  on  liberation  of  English  sparrows,  .        .        .       234 


Y. 

Yaroschev  on  ravages  of  the  gypsy  moth, 282 

Yellow-billed  cuckoo  destroying  the  gypsy  moth,  .  .  .  207,  212 
Yellow-throated  vireo  attacking  gypsy  moth  caterpillars, .  208,  217,  227 
Yellow  warbler  attacking  the  gypsy  moth, 208 


z. 

Zinc,  arsenate  of,  experiments  with, 480 

use  of,  on  trees, 189 

Zmiev,  ravages  of  the  gypsy  moth  in, 282 


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